記述言語：英語   掲載種別：研究論文（学術雑誌）  

A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a light absorbing, electron and hydrogen atom donor, and a household white light-emitting diode serves as a light source. The process transforms various N-sulfonylamide and -amine substrates to desulfonylated products in moderate to excellent yields. The observation that the fluorescence of 1-methyl-2-naphthoxy anion is efficiently quenched by the substrates suggests that the mechanism for the photoinduced desulfonylation reaction begins with photoexcitation of the naphthoxide chromophore in HONap-BIH, which generates an excited species via intramolecular proton transfer between the HONap and BIH moieties. This process triggers single electron transfer to the substrate, which promotes loss of the sulfonyl group to form the free amide or amine. The results of studies employing radical probe substrates as well as DFT calculations suggest that selective nitrogen-sulfur bond cleavage of the substrate radical anion generates either a pair of an amide or amine anion and a sulfonyl radical or that of an amidyl or aminyl radical and sulfinate anion, depending on the nature of the N-substituent on the substrate. An intermolecular version of this protocol, in which 1-methyl-2-naphthol and 1,3-dimethyl-2-phenylbenzimidazoline are used concomitantly, was also examined.

DOI： 10.1021/acs.joc.8b01536

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society  

Benzimidazolium naphthoxide (-ONap-BI+) was first synthesized and utilized as an unprecedented betaine photoredox catalyst. Photoexcited state of -ONap-BI+ generated by visible light irradiation catalyzes the reductive deiodination as well as desulfonylation reactions in which 1,3-dimethyl-2-phenylbenzimidazoline (Ph-BIH) cooperates with as an electron and hydrogen atom donor. Significant solvent effects on the reaction progress were discovered, and specific solvation toward imidazolium and naphthoxide moieties of -ONap-BI+ was proposed.

DOI： 10.1021/acs.joc.8b00282

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Visible light promoted reduction reactions of organohalides, sulfonamides, organonitriles and epoxy ketones were performed using 1,3-diinethylbenzimidazolines possessing 2-hydroxynaphthyl or 2-hydroxyphenyl substituents (HOAr-DMBIH) as photo-reductants. Xe or Hg-Xe lamp through an appropriate glass-filter (lambda>390 nm) and a household white light-emitting diode were used as light sources. In these reactions, reductive cleavages of carbon halogen, nitrogen sulfur, carbon carbon (nitrile) and carbon oxygen bonds take place. Bases exert significant effects on the progress of these reactions in a manner that depends on the nature of the substrate. Addition of 1,8-diazabicyclo[5.4.0]undec-7-ene as well as potassium t-butoxide significantly accelerates photo-reduction reactions of organohalides, sulfonamides and organonitriles while the decomposition of formed hydroxy ketones occurs in reactions of epoxy ketones. Single electron transfer from the photo-excited states of benzimidazolines (HOAr-DMBIH) or their deprotonated analogues (-OAr-DMBIH) to the substrates is proposed to initiate these reactions. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2016.05.078

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Oxidative ring-opening reactions of benzene-fused bicyclic cyclopropyl silyl ethers, promoted by copper(II) tetrafluoroborate, were investigated. The regioselectivity of cyclopropane ring-opening as well as product distributions were found to be highly dependent on the nature of the solvent. In alcohols, dimeric substances arising from external bond cleavage are major products. Radical rearrangement products are also formed in solvents such as ether and ethyl acetate. On the contrary, nucleophile addition to carbocation intermediates, generated by internal bond cleavage, occurs mainly in reactions taking place in acetonitrile. It is proposed that the observed solvent effects that govern the reaction pathways followed are a consequence of varying solvation of copper intermediates, which governs their reactivity and redox properties. In addition, the influence of counteranions of the copper salts, organonitriles, cyclic dienes, and substrate structures on the pathways followed in these reactions was also examined.

DOI： 10.1021/acs.joc.5b02827

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DOI： 10.1039/c5cc07562a

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その他リンク： http://orcid.org/0000-0002-0309-9507

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Photoinduced electron transfer (PET) reactions promoted by 2-aryl substituted 1,3-dimethylbenzimidazolines (Ar-DMBIH) were investigated. Excited states of Ar-DMBIH, formed by irradiation using light above 360 initiate PET reductions of various organic substrates, including transformations of epoxy ketones to aldols, free radical rearrangements such as the Dowd-Beckwith ring-expansion and 5-exo hexenyl cyclization, deprotection of N-sulfonyl-indols, and allylation of acyl formates. In these processes, Ar-DMBIH possessing 1-naphthyl, 2-naphthyl, 1-pyrenyl and 9-anthryl substituents formally act as two electron and one proton donors while the hydroxynaphthyl substituted derivative serves as a two electron and two proton donor. On the basis of the results of absorption spectroscopy studies, cyclic voltammetry and DFT calculation, a mechanistic sequence for these reduction reactions is proposed that involves initial photoexcitation of the aryl chromophore of the Ar-DMBIH followed by single electron transfer (SET) to the organic substrate to generate the radical cation of benzimidazoline and the radical anion of the substrate. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2015.06.071

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

A new sequential, one-pot protocol for transforming 1,3-disubstituted 2,3-epoxy ketones to β-hydroxy ketones and α-methylene ketones has been developed. Reaction of epoxy ketones with boron trifluoride etherate (BF3·OEt2) generates the cationic intermediates by regioselective epoxide ring opening and an acyl shift. Then, a treatment of these cations with 2-aryl-1,3-dimethylbenzimidazolines (DMBIH) results in formation of 1,2-disubstituted 3-hydroxy ketones. DMBIH serves as a hydride donor in the second step of this process. Finally, the β-hydroxy ketones can be converted to 1,2-disubstituted 2-methylene ketones by treatment with methanesulfonic acid or a combination of methanesulfonyl chloride and triethylamine. Importantly, the sequential steps involved in formation of the α-methylene ketone products can be carried out in one pot.

DOI： 10.1021/jo5025249

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CSIRO PUBLISHING  

2-Aryl-1,3-dimethylbenzimidazolines (DMBIHs) have been applied to photoinduced electron-transfer reductions of various organic substrates. Either direct or indirect electron transfer between the substrates and DMBIHs is utilized to promote the desired transformations. Photoexcitation of the substrates using light above 280 nm was carried out in the former protocol whereas a photosensitization method using materials such as substituted pyrenes, ruthenium and iridium complexes that absorb longer-wavelength light was employed in the latter. In these reactions, DMBIHs undergo initial electron transfer and subsequent proton or hydrogen atom transfer.

DOI： 10.1071/CH15314

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CSIRO PUBLISHING  

The visible light-promoted reduction reactions of some organohalides were investigated using 2-aryl-1,3-dimethylbenzimidazolines (Ar-DMBIH) possessing 2-naphthyl or 2-hydroxynaphthyl substituents. In these reduction reactions, singleelectron transfer from photo-excited Ar-DMBIH, attained by Xe lamp irradiation through an appropriate glass-filter (lambda > 390 nm), to the halide substrates leads to the carbon-halogen bond cleavage, followed by the rearrangements of the formed carbon radicals such as 5-exo hexenyl cyclization and the Dowd-Beckwith ring expansion. Addition of 1,8-diazabicyclo[5.4.0] undec-7-ene was found to enhance the reducing ability of hydroxynaphthyl-substituted DMBIH. A household white light-emitting diode was also used as a light source for these reactions.

DOI： 10.1071/CH15396

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

A combination of 2-aryl substituted 1,3-dimethyl-benzimidazolines (DMBIHs) and tris(2,2′-bipyridine)ruthenium(II) chloride, Ru(bpy)3Cl2was used to promote photoinduced electron-transfer (PET) reactions of α-halomethyl-substituted benzocyclic 1-alkanones. This photo-reagent system stimulates free radical forming, cleavage of both carbon-bromine and carbon-chlorine bonds that are not activated by carbonyl groups. The resulting free radicals undergo 5-exo hexenyl cyclization as well as sequential cyclization and ring-expansion (Dowd-Beckwith) reactions to form radicals that abstract hydrogen atoms from the radical cation of DMBIH to yield the observed products. The results of a study of the effects of substituents located on the 2-aryl ring of DMBIH suggest that steric and hydrogen-bonding interactions influence the nature of the reaction pathways followed by the radical intermediates. PET reactions using an iridium complex and DMBIH were also investigated. © 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2014.02.078

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出版者・発行元：Elsevier {BV}  

DOI： 10.1016/j.tetlet.2014.03.115

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出版者・発行元：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/c4cc02536a

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

A photoreaction between benzoyl compounds, such as benzoylformate derivatives, and 2-(p-anisyl)-1,3-dimethylbenzimidazoline in the presence of allyl bromide was found to give various allylated alcohols. In the reaction of benzoylformates, cc-hydroxy ester enolates, for which the negative charge occurs on the carbonyl carbon of benzoyl (umpolung reactivity), are proposed to be generated as intermediates by electron-transfer from benzimidazolines to the photoexcited benzoylformates; these species react with allyl bromide to produce alpha-allyl-alpha-hydroxy esters. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2013.10.028

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BEILSTEIN-INSTITUT  

Copper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives were investigated. The regioselectivities of these processes were found to be influenced by the structure of cyclopropanols as well as the counter anion of the copper(II) salts. A mechanism involving rearrangement reactions of radical intermediates and their competitive trapping by copper ions is proposed.

DOI： 10.3762/bjoc.9.156

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記述言語：英語  

Photoinduced electron-transfer reaction of α-bromomethyl-substituted benzocyclic β-keto esters with tertiary amines was investigated. Debrominated β-keto esters and ring-expanded γ-keto esters were obtained as major products. On the basis of mechanistic experiments it was concluded that these products are formed via a reaction sequence of selective carbon-bromine bond cleavage and subsequent competitive hydrogen abstraction and Dowd-Beckwith ring-expansion of the resulting primary alkyl radicals. The characteristic product distribution observed for the type of amine used is rationalized on the basis of selective reaction pathways of generated radical intermediates that depend on the nature of the amine radical cations. © 2012 Springer Science+Business Media B.V.

DOI： 10.1007/s11164-012-0646-2

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記述言語：英語   出版者・発行元：Japan Institute of Heterocyclic Chemistry  

A unique and simple preparative method for N-cyano--aryl pipecolinic acid esters via base-induced Sommelet–Hauser rearrangement, the von Broun reaction, and intramolecular -alkylation is reported. The removal of the N-cyano substituent was achieved by hydrogenation and hydride reduction.

DOI： 10.3987/COM-12-12619

DOI： 10.3987/com-12-12619

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記述言語：英語   出版者・発行元：Elsevier {BV}  

The 1,4-elimination reaction of (Z)-N-Boc-2-(4-methoxy-2-alkenyloxy)amines with Brønsted acids catalyzed aza-Ferrier reaction of the 1,4-eliminated product, thus obtained, afforded various β-amino-β,γ-unsaturated aldehydes. The scope and limitation of this sequential reaction are described.

DOI： 10.1016/j.tet.2013.01.088

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DOI： 10.1021/jo400239h

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その他リンク： http://orcid.org/0000-0002-0309-9507

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Aza-Prins cyclization reactions of N-tosyl-3-butenylamine with p-methoxybenzaldehyde, 1-naphthaldehyde and 2-naphthaldehyde take place efficiently using a combination 1-butyl-3-methylimidazolium of ferric chloride and hexafluorophosphate in benzotrifluoride (Felm-BTF procedure). The new methodology, leading to formation of target N-tosyl-4-chloro-2-substituted piperidines, is superior to the one using 1-butyl-3-methylimidazolium tetrachloroferrate. The Felm-BTF procedure was also applied to aza-Prins cyclization reactions of other aldehydes. Finally, the effects of imidazolium salts on aza-Prins cyclization reaction promoted by boranetrifluoride-diethyl ether complex, leading to formation of fluorinated piperidines, were explored.

DOI： 10.3987/COM-12-S(N)78

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記述言語：英語   出版者・発行元：Elsevier {BV}  

The intermolecular aromatic substitution of N,N-dialkylanilines and alkoxybenzenes with diazoesters is shown to proceed in the presence of catalytic amounts of both copper(II) salt and acid (Lewis or Brønsted). This method is a mild and rare metal-free C–C bond formation reaction between aromatic (sp2) and aliphatic (sp3) carbons.

DOI： 10.1016/j.tetlet.2012.07.070

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記述言語：英語   出版者・発行元：Royal Society of Chemistry ({RSC})  

Asymmetric α-2-tosylethenylation of (S)-2-(pyrrolidin-1-yl)propanoic acid esters was shown to produce good yields with high enantioselectivities. The reaction proceeds via the formation of a non-racemic ammonium enolate without an external source of chirality.

DOI： 10.1039/c1ob06074k

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記述言語：英語   出版者・発行元：Elsevier {BV}  

Selective amine de-alkylation enables the conversion of Sommelet–Hauser rearrangement products into 2-aryl-2-bromoacetic acid derivatives. These compounds are valuable synthetic intermediates in the synthesis of α-aryl-α-amino or α-aryl-β-amino acid derivatives. The method presented herein is a formal de-N,N-dialkylation of Sommelet–Hauser rearrangement products.

DOI： 10.1016/j.tet.2012.04.015

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記述言語：英語   出版者・発行元：Elsevier {BV}  

A new protecting group, 1,2-dimethoxy-4,5-dimethylene, for acyclic amino acid derivatives could be introduced by N,N-dialkylation with 1,2-bis(bromomethyl)-4,5-dimethoxybenzene (1) and removed via amine de-alkylation with acyl chlorides. The method can be used with baseinduced [2,3] and [1,2] Stevens rearrangement products.

DOI： 10.1016/j.tetlet.2012.01.013

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記述言語：英語   出版者・発行元：Elsevier {BV}  

Asymmetric -2-tosylvinylation of N-substituted proline esters using ethynyl tolyl sulfone as an electrophile was shown to proceed in good yield with high enantioselectivities without the addition of any bases. The reaction proceeds via the formation of N-2-tosylvinyl ammonium ylides.

DOI： 10.1016/j.tetlet.2011.02.040

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Aza-Prins cyclization reaction of N-tosyl-3-butenylamine with aliphatic and aromatic aldehydes was performed using a combination of FeCl3 and 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)) or 1-butyl-3-methylimidazolium tetrachloroferrate (BmimFeCl(4)) in benzotrifluoride (BTF). The desired N-tosyl-4-chloro-2-substituted piperidines were obtained from aliphatic aldehydes in comparable yields to those for the previously reported reactions in which FeCl3 was used in CH2Cl2. On the other hand, significant progress for the piperidine synthesis from aromatic aldehydes has been achieved, particularly when BmimFeCl(4) was used with FeCl3 in BTF. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2010.10.018

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Ferric chloride (FeCl3) promoted electron transfer oxidation of bicyclic cyclopropyl silyl ethers was performed in biphasic solution system of 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)) and benzotrifluoride (BTF). The resulting chloro-substituted ring-expanded cycloalkanones were treated with an appropriate base to produce substituted cyclic enones. These two-step reactions were successfully devised to proceed in a simpler manner in which the ordinary work-up operations for the former oxidation step, such as water-quench, extraction, and evaporation, were omitted; imidazole was found to be the most suitable base for the latter elimination step. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2010.03.029

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出版者・発行元：Wiley  

DOI： 10.1002/ejoc.201001083

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記述言語：英語   出版者・発行元：Elsevier {BV}  

A solution of potassium tert-butoxide in THF was shown to remarkably enhance the baseinduced Sommelet–Hauser rearrangement of N-benzylic amino acid-derived ammonium ylides.

DOI： 10.1016/j.tet.2010.09.105

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Tris(p-bromophenyl)aminium hexachloroantimonate and perchlorate were utilized to promote the oxidative ring-opening reaction of cyclopropyl silyl ethers giving ring-expanded ketones. Exploration of salt quantity effect on the reaction allowed us to hypothesize that amine radical cation is regenerated through the oxidation of neutral amine by hexachloroantimonate anion. Based on this hypothesis, amine radical cation was initially generated by the treatment of parent amine with either antimony pentachloride or the mixture of silver perchlorate and molecular iodine, and subsequently reacted with same substrates. The in situ generated amine radical cation was found to promote the reaction, and the expected products were obtained in better yields than via use of the corresponding salt reagents. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2009.09.108

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Samarium diiodide promoted reaction of various alpha-bromomethyl cycloalkanones, followed by subsequent treatment with trimethylsilyl chloride, leads to the production of cyclopropyl silyl ethers embedded in bicyclo[m.1.0]alkane frameworks. Treatment of the ethers with oxidative electron-transfer reagents, such as Fe(III), Ce(IV), and Mn(III) salts, generates ring-expanded ketones that convert to cyclic conjugated enones in moderate to good yields. In addition, the reduction-oxidation reaction sequences can be successfully performed in one pot. The regioselectivities of cyclopropane ring opening in the bicyclic Substrates depend on the oxidizing agents used. For example, reactions promoted by FeCl3 with pyridine lead to the expected ring-expansion process involving internal-bond cleavage of bicycloalkane and yielding cyclic enones as final products. In contrast, reactions with Ce(NH4)(2)(NO3)(6) or Mn(OAc)(3) as oxidizing agents proceed by way of external-bond cleavage to give alpha-iodomethyl cycloalkanones.

DOI： 10.1021/jo802749g

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

2-(p-Methoxyphenyl)-1,3-dimethylbenzimidazoline (ADMBI) and 2-(o-hydroxyphenyl)-1,3-dimethylbenzimidazoline (HPDMBI) are used as reducing reagents in 1,8-dimethoxypyrene (1,8-DMP) sensitized, photoinduced electron transfer (PET) reactions. This system was effectively used for PET induced, reductive transformations of various organic substrates, including alpha,beta-epoxy ketones, the olefin tethered 2-bromomethyl-1-tetraone, and o-allyloxy-iodobenzene, as well as for the deprotection reactions of dodecyl-2-benzoylbenzoate and N-sulfonylindole. The results of studies show that 1,8-DMP is a more effective sensitizer than the previously used 9-methylcarbazole for deprotection of N-methyl-4-picolinium ester.

DOI： 10.3987/COM-08-S(F)94

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Tris(trimethylsilyl)silane (TTMSS) promoted free radical reaction in benzotrifluoride (BTF) was investigated. Compared to same reaction using environmentally less desirable tri-n-butyltin hydride (TBTH) in benzene, less quantity of BTF than that of benzene can be used because of slower hydrogen atom transfer from TTMSS than that from TBTH toward primary alkyl radicals. Also, electron-transfer reactions promoted by tris(p-bromophenyl)aminium hexachloroantimonate (TBPA) and FeCl(3) were conducted in BTF. Then, TBPA was found to be effective in BTF comparably to that in methylene chloride. In addition, an interesting observation that FeCl(3) promoted reaction was accelerated by the addition of imidazolium salt was made. All the results suggest that BTF is a tolerable solvent for free radical reaction with TTMSS and electron-transfer reactions using TBPA as well as FeCl(3). (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2008.06.012

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Oxidative ring-opening reactions of cyclopropyl silyl ethers incorporated into bicyclo[m.1.0]alkane framework were investigated. The results show that the regioselectivities for ring-opening of intermediate radical cations, formed by single electron transfer, are governed by the nature of the nucleophile as well as oxidizing species.

DOI： 10.1021/ol0709937

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

The reaction of samarium diiodide with some cyclic and acyclic ketones tethering acyloxyalkyl side chains produced 2-hydroxy cyclic hemiacetals in moderate to good yields, in which an intramolecular addition of samarium ketyl radicals to distant ester carbonyls would be involved. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2006.08.126

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Photoinduced electron-transfer reactions of several ketone substrates were studied to evaluate the utilities of 1,6-bis(dimethyl-amino)pyrene (BDMAP), 1,6-dimethoxypyrene (DMP), 9,10-bis(dimethlylamino)anthracene (BDMAA), and 9,10-dimethoxyanthracene (DMA) as electron-donating sensitizers cooperating with 2-aryl-13-dimethylbenzimidazolines. BDMAP and DMP generally led higher conversion of ketones and better yield of reduction products compared to BDMAA and DMA. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2006.03.061

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CHEMICAL SOC JAPAN  

FeCl3-promoted regioselective ring-opening reactions of cyc lopropyl trimethylsilyl ethers, obtained by SMI2 reduction c followed by silylation with Me3SiCl of bromoalkyl ketones and acyl chloride, were performed. Eventually, the sequential reduction and oxidation reactions starting from bromoalkyl ketones to give ring-expanded enones were achieved in one-pot.

DOI： 10.1246/cl.2005.1688

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

[GRAPHICS]
In the photoreaction of benzophenones with 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI), benzhydrols were major products. Addition of H2O accelerated the reaction with no change in the product distribution, while AcOH, PhOH, and metal salts such as LiClO4 and Mg(ClOL4)(2) were effective additives to produce benzpinacols. In contrast, benzpinacols were exclusively formed regardless of the solvent and the additive in the reactions with 2-(o-hydroxyphenyl)-1,3-dimethylbenzimidazoline (o-HPDMBI). These observations are consistent with the hypothesis that DMPBIcenter dot+ donates a proton at the C-2 position to the benzophenone ketyl radicals while o-HPDMBIcenter dot+ donates a phenol proton.

DOI： 10.1021/jo0514220

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CHEMICAL SOC JAPAN  

Both 2-(2-hydroxyphenyl)-1,3-dimethylbenzimidazoline and 2-(4-hydroxyphenyl)-1,3-dimethylbenzimidazoline were found to act as formal two hydrogen atom-donors for photoinduced electron transfer reactions of epoxy ketones and other carbonyl compounds.

DOI： 10.1246/cl.2004.18

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

When 2-substituted alkyl 1-indanone-2-acetates 1 were treated with samarium diiodide, 3-substituted 2-hydroxy-2,3-methano-1-oxo-1,2,3,4-tetrahydronaphthalenes 4 were obtained. The reaction is proposed to proceed through a rearrangement initiated by intramolecular ketone-ester coupling. Oxidation of these products 4 or their silyl ethers 13 by ceric(IV) ammonium nitrate involving regioselective bond cleavage of their bicyclo[4.1.0]-rings produced the corresponding benzotropolone derivatives 10. (C) 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2003.10.083

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

When ethyl 2-substituted-1-indanolle-2-carboxylates were treated with samarium diiodide (Sml(2)), ring expansion products such as 3-substituted-1,2-naphthoquillones were isolated. Alcohols were also obtained as the mixture of cis- and trans-isomers of hydroxy and ester substituents. A reaction mechanism involving intranlolecular addition of samarium ketyl radicals to ester substituents followed by ring expansion was proposed for the formation of the one-carbon homologated products. Similarly, reaction of ethyl 1-substituted-2-oxo-1-cyclopentanecarboxylates with Sml(2) produced 3-substituted-2-hydroxy-2-cyclohexenones along with the corresponding alcohols. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(02)01007-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Photoinduced electron transfer reaction of 2-bromomethyl-2-( 3-butenyl)benzocyclic-1-alkanones with amines afforded 5-exo radical cyclization products while electron transfer reaction with samarium diiodide produced cyclopropanols.

DOI： 10.1039/b205781f

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

A combination of 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI) and acetic acid has been utilized for photoinduced reductive transformation of α,β-epoxy ketones to β-hydroxy ketones. Study on photoreactions using several proton donors revealed that acetic acid is superior to other proton donors such as HCl, p-TsOH, MeOH, and water. 1,3-Dimethyl-2-phenylbenzimidazolium was produced in the reaction with acetic acid while N-benzoyl-N,N′-dimethyl-o-phenylenediamine was formed in aqueous solvents. When THF solutions containing aryl carbonyl possessing α,β-epoxy ketones and DMPBI and acetic acid were irradiated (λ > 280 nm), β-hydroxy ketones were isolated in good to excellent yields. Photosensitized conditions (λ > 340 nm) were employed for the reactions of alkyl carbonyl possessing α,β-epoxy ketones.

DOI： 10.1055/s-2001-15055

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Reaction of ethyl 2-haloethyl-1-tetralone-2-carboxylates and SmI2 produced novel dimers possessing cyclic ether structures through intramolecular O-alkylation of samarium ketyl radicals by carbon-halogen bonds. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(00)01020-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Photoreactions of 4-(tribromomethyl)-4-methyl-2,5-cyclohexadienone (1) and its derivatives with amines were studied. Irradiation of 1 with amine produced 4-bromo-5-methyltropone (2) along with 4-(dibromomethyl)-4-methyl-2,5-cyclohexadienone (3). The effects of solvent, added water, and the structural variation in amine on the product ratio were explored. Isolation of the amine-derived products revealed that oxidative dealkylation of amine proceeded during the photoreaction. On the basis of the results obtained, a reaction mechanism involving fragmentation of the dienone anion-radical and amine cation-radical pair is proposed. Photoreactions of dienone 4 with amine produced the tropones 6 and 7, whereas tropone 9 was produced from 8. Trialkyltin radical-induced reductions of dienones land 4 with tri-n-butyltin hydride demonstrated common features with the photoreactions. It was also found that irradiation of dienone 3 with amine produced 4-methyltropone (10).

DOI： 10.1021/jo990215v

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photoreactions of epoxy ketones, aromatic ketones, haloketones, and aromatic halides with 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI) were studied. Photoinduced single-electron transfer from DMPBI to such substrates initiates the reactions, followed by radical rearrangement and reduction to finally give several reduced products in modest to good yields.

DOI： 10.1016/S0040-4020(99)00804-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

SmI2reductions of some aromatic as well as aliphatic α-bromomethyl cyclic β-keto esters produced one-carbon homologated γ-keto esters in modest to good yields.

DOI： 10.1016/S0040-4039(98)00658-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Royal Society of Chemistry  

Photoreaction of ethyl 2-bromomethyl-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carboxylate 1a or other related compounds 1b-d with Me3SiCH2NEt2 in aqueous MeCN afforded ethyl 5-oxo-6,7,8,9-tetrahydrobenzocycloheptene-7-carboxylate 2a or corresponding ring expansion products 2a-d respectively.

DOI： 10.1039/a703974c

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photoreaction of trans-1-(4-cyanophenyl)-3-phenyl-2,3-epoxy-1-propanone (trans-4′-cyanochalcone epoxide) with various electron donors was studied. Irradiation of this epoxy ketone with amines produced 1-(4-cyanophenyl)-3-phenyl-1,3-propanedione and 1-(4-cyanophenyl)-3-hydroxy-3-phenyl-1-propanone in various ratios depending on the kinds of amine and solvent used. A reaction mechanism involving an amine cation radical-assisted rearrangement of the epoxy ketone anion radical was proposed to be most consistent with the marked change in the yield of β-diketone. On the other hand, the timing of proton transfer to the anionic intermediates is considered to be a key factor to yield the β-hydroxy ketone. Information obtained from the photochemical study was useful to find the reaction conditions for the conversion of several aromatic epoxy ketones to hydroxy ketones by the use of samarium diiodide. Addition of methanol significantly changed the product distribution. Proper choice of water or methanol as a proton source produced hydroxy ketones in moderate to good yields.

DOI： 10.1021/jo9622439

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Catalytic amounts of triarylpyrylium sales photochemically and thermally promoted the substitution reactions of dimethyl acetals with silylated nucleophiles. Copyright (C) 1996 Elsevier Science Ltd.

DOI： 10.1016/0040-4039(96)01776-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Irradiation of aroyl substituted epoxy ketones with 2-phenyl-N,N-dimethylbenzimidazoline in aqueous tetrahydrofuran or aqueous benzene produced the corresponding aldols in good to excellent yields. Changing the amount of water added significantly influenced the product distribution.

DOI： 10.1016/0040-4039(96)01578-X

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

A catalytic amount of tris(p-bromophenyl)aminium hexachloroantimonate promoted the substitution reactions of dimethylacetals with various silylated nucleophiles through an election transfer mechanism. Silyl compounds include silyl enol ether, ketene silyl acetal, and allylsilane. One methoxy group of the substrates was effectively substituted by nucleophiles to form carbon-carbon bonds. Copyright (C) 1996 Elsevier Science Ltd

DOI： 10.1016/0040-4039(96)00596-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Irradiation of 2,2-dimethyl-13-diphenyl-13-propanedione in the presence of triethylamine gave anti-2,2-dimethyl-13-diphenyl-13-cyclopropanediol as a major product. On the basis of the results obtained, the mechanism involving single electron transfer between the excited diketone and the ground state amine followed by the anion radical rearrangement was proposed. The same cyclized product was also obtained for the reaction with samarium diiodide.

DOI： 10.1016/00404-0399(50)1429L-

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Irradiation of 2,2-dimethyl-13-diphenyl-13-propanedione in the presence of triethylamine gave anti-2,2-dimethyl-13-diphenyl-13-cyclopropanediol as a major product. On the basis of the results obtained, the mechanism involving single electron transfer between the excited diketone and the ground state amine followed by the anion radical rearrangement was proposed. The same cyclized product was also obtained for the reaction with samarium diiodide.

DOI： 10.1016/00404-0399(50)1429L-

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Reaction of 1-bromo-1-phenyl-3-(1-naphthyl)-23-epoxypropane 1 with samarium diiodide afforded 1-phenyl-2-(1-naphthylmethoxy)ethene 3 as well as 1-(1-naphthyl)-3-phenylprop-2-enol 2. The product distributions were influenced by various factors, such as additives, concentrations, and reaction temperature.

DOI： 10.1016/0040-4039(95)00975-I

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Reaction of 1-bromo-1-phenyl-3-(1-naphthyl)-2,3-epoxypropane 1 with samarium diiodide afforded 1-phenyl 2-(1-naphlhylmethoxy)ethene 3 well as 1-(1-naphthyl)-3-phenylprop-2-enol 2. The product distributions were influenced by various factors, such as additives, concentrations, and reaction temperature.

DOI： 10.1016/00404-0399(50)0975I-

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Irradiation of 4-tribromomethyl-4-methyl-2,5-cyclohexadienone in the presence of amines gave 4-bromo-5-methyltropone as a major product. On the basis of the results obtained, the mechanism involving single electron transfer from the amine ground state to the dienone excited state was proposed.

DOI： 10.1016/S0040-4039(00)78459-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photoreactions of various dithioacetals and ketals using tris(p-chlorophenyl)pyrylium perchlorate as a sensitizer were studied. Irradiation (λ&amp
&gt
360 nm) of dichloromethane solutions containing dithioacetals or ketals and pyrylium salt afforded the corresponding carbonyl compounds in good to excellent yields in the presence of molecular oxygen. © 1994.

DOI： 10.1016/S0040-4020(01)81203-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

The first bimolecular rate constants for the reduction of a primary alkyl radical by SmI2 were obtained by using a competitive hexenyl radical clock. Rate constants varied from 5 x 10(5) to 7 x 10(6) M-1 s-1, depending on the amount of HMPA present.

DOI： 10.1016/S0040-4039(00)60760-8

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DOI： 10.1021/jo00070a046

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

It was confirmed that the cyclization product of α-(phenoxy)phenylacetic acid (1 a) with polyphosphoric acid is 3-phenyl-2(3 H)-benzofuranone (3 a) instead of 2-phenyl-3(2 H)-benzofuranone (2 a). Some mechanistic studies including crossover experiments by use of la and α-(p~methylphenoxy)-p-tolylacetic acid (1 d) demonstrated that the rearrangement occurs intramolecularly. The rearrangement of benzyl phenyl ethers with polyphosphoric acid was also investigated. © 1993, The Chemical Society of Japan. All rights reserved.

DOI： 10.1246/nikkashi.1993.363

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

DOI： 10.1021/jo00049a054

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Free-radical reactions of α,β-epoxy ketones with tributyltin hydride have been studied. These substances were selectively converted to β-hydroxy ketones under both photochemical and thermal conditions. The photoreaction is initiated by hydrogen abstraction of an epoxy ketone triplet from tributyltin hydride, while azoisobutyronitrile is used as an initiator for the thermal reaction. In general, the photoreaction conditions are particularly useful for aroyl-substituted epoxy ketones while the thermal conditions are applicable to a variety of epoxy ketones. It was also found that the epoxy esters and epoxy alcohols did not undergo the ring-opening reaction under the similar conditions. Tributyltin radical attack on the carbonyl of epoxy ketones is a key process for both the photoreaction and the thermal reaction. Regioselective ring opening of the resulting oxiranylmethyl radical finally produces β-hydroxy ketones. In order to capture the free-radical intermediates, the reaction of epoxy ketones with allyltributyltin was conducted. The isolation of α-allylated β-hydroxy ketones is interpreted by the involvement of a novel 1,5-tributyltin transfer. © 1992, American Chemical Soc

DOI： 10.1021/jo00046a016

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

Photosensitized oxygenation reactions of 2-(p-methylphenyl)-1,3-dithiane 1a, and 2,2-di-(p-methylphenyl)-1,3-dithiane 1b afforded carbony compounds, sulfoxides, and sulfones at the various ratios through cooperative single electron transfer (SET) pathway and singlet oxygen pathway.

DOI： 10.1016/S0040-4039(00)61196-6

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Thiopyrano[4,3,2‐cd]benzofuran 9 possessing benzofuran and methylenethiopyran structures in the molecule was synthesized starting from 1‐chloro‐4‐methoxy‐2‐nitrobenzene 11. Some reactions (formylation, protonation and catalytic hydrogenation) on 9 were examined. The 2‐position of 9 was highly reactive toward electrophilic reagents and the furan ring was readily reduced by catalytic hydrogenation with palladium‐charcoal. Thiopyrano[4,3,2‐cd]benzofuran 9 has both properties of methylenethiopyran and benzofuran. Copyright © 1992 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570290236

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

A variety of 1,3-dithianes was converted to the corresponding carbonyl compounds in good yields when those substances were treated with antimony pentachloride in methylene chloride. Single electron transfer from dithianes to antimony pentachloride was proposed as an initiation step of the reaction.

DOI： 10.1016/0040-4039(91)80123-N

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Irradiation of aromatic α,β-epoxy ketones in the presence of allyltributyltin afforded α-allyl-β-hydroxy ketones by a single electron transfer mechanism. © 1991.

DOI： 10.1016/S0040-4039(00)78899-X

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Photosensitized [2+2] cycloreversion reactions of arylated cage compounds 1 to dienes 2 using several cyanoaromatics as sensitizers are reported. In acetonitrile, 1a isomerized to 2a via an efficient cation-radical chain process. In contrast, the isomerization of 1a to 2a proceeded via an exciplex in benzene. Interestingly, the exciplex emission maximum observed in the fluorescence quenching by 1a was the same as that by 2a. Such a coincidence was also observed in a series of arylated cage compounds 1a-d and dienes 2a-d in various solvents. These observations together with the results obtained from reaction and exciplex emission quenching experiments clearly demonstrated the occurrence of adiabatic exciplex isomerization of 1 to 2. Efficiencies (A(e)) of the adiabatic process obtained by comparing the intensities of the observed exciplex emissions with those of diene exciplex emissions were quite high and became almost quantitative in some cases. A(e) values were found to increase as (1) the oxidation potentials (E1/2ox) of cage compounds 1a-d decreased, (2) the reduction potentials (E1/2red) of sensitizers increased, and (3) the solvent polarity (E(T)) increased.

DOI： 10.1021/jo00006a039

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photoinduced single electron transfer (SET) reactions of α,β-epoxy ketones have been studied using alkylamine electron donors. Irradiation of chalcone epoxide 1 with triethylamine (TEA) afforded β-diketone 2 and β-hydroxy ketone 3. Photoreaction of 1 with TEA in MeOH resulted in a slightly increased product ratio (3/2) compared with that in MeCN. When 1,4-diazabicyclo[2.2.2]octane (DABCO) was used instead of TEA, a decrease in the yield of 3 was observed. Only 2 was obtained on irradiation of a solution of 1 in TEA and MeCN containing LiClO4. Studies of photoreactions of dypnone epoxide 9, benzoylisopropylethylene epoxide 12, and acrylophenone epoxide 15 indicate that the nature of β-substituent also influences the product distribution. It was also found that 1,6-bis(dimethylamino)pyrene (BDMAP) sensitizes the photoreaction of 1 in the presence of TEA to produce 2. Based on the results obtained, a reaction mechanism involving selective Cα–O bond cleavage of intermediate α,β-epoxy ketone anion radicals is proposed. © 1991, American Chemical Society. All rights reserved.

DOI： 10.1021/jo00004a052

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Triphenylpyrylium salt sensitized photoreactions of several dithianes and dithiolanes produced carbonyl compounds in good yields in the presence of molecular oxygen. Molecular oxygen trapping of carbon radical intermediates generated through selective CS bond cleavage of dithiane and dithiolane cation radicals is proposed. © 1991.

DOI： 10.1016/S0040-4039(00)92167-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Irradiation of 8-alkoxytetrahydro-1-naphthalenones 5 gave rearranged naphthyl alcohols 11 as major products and in contrast, 4- alkoxytetrahydrobenzocyclohepten-5-ones 6 afforded tetrahydrocyclohepta[cd] benzofurans 14 in good yields
the difference in reactivities is attributed to the conformation of six- and seven-membered rings.

DOI： 10.1039/C39910000044

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photocyclization reactions were carried out on 2‐alkoxybenzaldehydes 1a‐f, 2′‐alkoxyacetophenones 2a‐h, 2‐formylphenoxyacetic acids 1i‐l and 2‐acetylphenoxyacetic acids 2i‐m. Irradiation of 1a‐f and 2a‐h in acetonitrile gave the corresponding dihydrobenzofuranols 3, 5 and dihydroisobenzofuranols 4, 6. Using carboxylic acids 1i‐1, 2i‐m as starting materials, decarboxylation occurred immediately to give the corresponding ethers 1a‐d, 2a‐e. Further irradiation of the solution afforded dihydrobenzofuranols 3, 5 and dihydroisobenzofuranols 4, 6. Substituent effects on photocyclization and reaction pathways are discussed. Copyright © 1991 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570280518

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Photocyclization reactions were carried out on ethyl 2‐formylphenoxyacetates 1a‐e and ethyl 2‐acetylphenoxyacetates 2a‐e in acetonitrile. Irradiation of 1a‐e gave dihydrobenzofuranols 3 in 20–46% yields. Similarly, irradiation of 2a‐e afforded dihydrobenzofuranols 6 and their derivatives 7, 8 in 40–86% yields. Substituent effects on photocyclization and reaction pathways are discussed. Copyright © 1991 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570280519

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Several α,β-epoxy ketones were converted to aldols in good yields upon irradiation or heating with azoisobutyronitrile in the presence of tributyltin hydride in benzene; the reactions involve selective C α-O bond cleavage of the oxiranylmethyl radicals derived from these substances.

DOI： 10.1039/C39900000550

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The Cβ-O bonds of chalcone epoxides (1a, 1b) were selectively cleaved by pyrylium salt sensitized photoreactions, affording β-ketoaldehydes (2a, 2b) in CH2Cl2and MeOH-adducts (3a, 3b) in MeOH. Similarly. cerium(IV) salts catalyzed the MeOH-adduct formations of 1a and 1b in the dark. On the other hand, nitrate ester (4b) was obtained on treatment of 1b with a cerium(IV) salt in MeCN. © 1990.

DOI： 10.1016/S0040-4039(00)94495-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Tetrahydrocyclohepta[cd]benzofurans 7a‐e were synthesized by the treatment of (5‐oxo‐tetrahydro‐5H‐benzocyclohepten‐4‐yloxy)acetic acids 5a‐e with sodium acetate in acetic anhydride or by heating of their esters 6a‐e with sodium hydroxide or sodium hydride in dioxane. The yield of furans 7 decreased as a substituent R of acids 5 or esters 6 was changed from hydrogen to a methyl, ethyl, or isopropyl group. When R was a phenyl group furan 7e was always prepared in good yield. Sodium hydride was a useful base for synthesis of tetrahydrocyclohepta[cd]benzofurans. Copyright © 1990 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570270421

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

A variety of 2,5‐dioxacyclohepta[jkl]‐as‐indacenes 5, 7–14 were synthesized as a new heterocycle by the treatment of diethyl (5,9‐dioxobenzocyclohepten‐1,4‐diyloxy)diacetates 4a‐e with potassium hydroxide or sodium hydride in dioxane. The mechanism of furan‐ring formation from 4a‐e was discussed. Copyright © 1990 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570270422

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

The hitherto unknown examples of cation radical isomerizations of tricyclo[4.2.0.02,5]octane and 1,5-cyclooctadiene derivatives are reported. Photoreaction of l,2,5,6-tetraphenyltricyclo[4.2.0.02,6]octane (1) with 9,10-dicyanoanthracene (DCA) afforded 1,2,5,6-tetraphenyl-1,5-cyclooctadiene (2) and 1,2,5,6-tetrapheny1tricyc1o[3.3.0.02,6(3). Upon a similar irradiation, 2 was converted to 3. Likewise, other electron acceptors, such as tetracyanoethylene (TCNE), 1,2,4,5-tetracyanobenzene (TCNB), and tris(p-bromophenyl)aminium hexachloroantimonate, catalyzed these reactions. Quenching experiments using 1,2,4,5-tetramethoxybenzene (TMB) and naphthalene (NAP) supported the occurrence of cation radical isomerizations among 1, 2, and 3. © 1989, American Chemical Society. All rights reserved.

DOI： 10.1021/jo00270a013

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記述言語：英語  

DOI： 10.1021/ja00183a081

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyclohepta[cd]benzofuran 2 was synthesized by heating (5‐oxo‐5H‐benzocyclohepten‐4‐yloxy)acetic acid 16 with sodium acetate in acetic anhydride or by photocyclization of 16 in acetonitrile. Several reactions of cyclohepta[cd]benzofuran 2 were examined. Protonation of 2 with trifluoroacetic acid occurred at the 2‐position to give a tropylium ion 17. Catalytic hydrogenation of 2 with palladium on charcoal proceeded smoothly to give tetrahydrocyclohepta[cd]benzofuran 18. The Diels‐Alder reaction of 2 with tetracyano‐ethylene produced an adduct 19. Formylation of 2 with phosphorus oxychloride and dimethylformamide occurred easily at the 2‐position to afford compound 20. Cyclohepta[cd]benzofuran 2 has both properties of heptafulvene and benzofuran. Copyright © 1989 Journal of Heterocyclic Chemistry

DOI： 10.1002/jhet.5570260218

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

Studies were conducted to explore single electron transfer (SET) induced photoaddition reactions of 9,10-dicyanoanthracene (DCA) with a variety of n-electron donors including silicon-containing substrates (EtOCH2TMS, EtSCH2TMS, and Et2NCH2TMS). Photoadditions of EtOCH2TMS and EtSCH2TMS to DCA in MeCN occur in high yields to produce 10-substituted 9,10-dicyano-9,10-dihydroanthracenes in which the anthracenyl unit is bonded to the ether or thioether in place of the TMS substituent. The photoadducts undergo base-induced dehydrocyanation and oxidation to generate the respective 10-substituted 9-cyanoanthracenes and 10-substituted 10-cyano-9-anthrones. Photoaddition of Et2NCH2TMS to DCA in MeCN produces the corresponding dihydroanthracene adduct, which spontaneously dehydrocyanates under the reaction conditions to yield the corresponding 10-substituted 9-cyanoanthracene. This process is inefficient as compared to the O and S analogues; other products from this reaction include 9-cyano-10-aminoanthracene, 9-cyanoanthracene, and 9-cyano-10-methylanthracene. The latter product is shown to arise by secondary photoreaction of the Et2NCH2TMS-DCA anthracene adduct. Mechanisms for these photoad

DOI： 10.1021/jo00258a007

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The photoaddition reactions of a series of conjugated cyclohexenones with the tertiary α-silyl amine Et2NCH2TMS have been subjected to exploratory and mechanistic investigation. In general, photoadditions in these systems occur to generate in modest to good yields adducts resulting from carbon-carbon bonding between the enone α-carbons and amine silicon-substituted α-carbon. These processes lead to formation of TMS and non-TMS adducts corresponding to substitution by the enone grouping for hydrogen or the trimethylsilyl grouping in the amine. The polarity and protic nature of solvents used for these photoreactions appear to control the TMS to non-TMS adduct ratios, with the former being favored in low-polarity aprotic media (MeCN) and the latter in polar protic media (MeOH). A more detailed investigation of this phenomenon by using the photoadditions of 4,4-dimethylcyclohex-2-en-1-one with Et2NCH2TMS has uncovered the source of this control. Accordingly the non-TMS to TMS adduct ratio in this system is found to be directly dependent upon the solvent polarity (Eτor AN values) and protic nature. Likewise, this ratio increases when the salts LiClO4and n-Bu4NClO4are present in the

DOI： 10.1021/ja00232a023

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Norbornadiene-quadricyclane photo-thermal isomerization system is one of the most important and popular solar energy storage system. However, norbornadiene itself does not possess any absorption band in visible light region where the solar light energy is the most dense-region. For efficient utilization of solar light energy, norbornadienes [1] which possess a chalcone chromophore were synthesized by Diels-Alder reaction of cyclopentadiene with dehydrochalco-nes. Photoisomerization reactions of [1] gave corresponding quadricyclane derivatives [2] in good yields. The quantum yields of the isomerizations are 0.06~0.60. The properties of [1] and [2], and the results of the reactions are shown in Table 1. Solvent effects and wavelength dependency of the isomerizations are also presented. Isomerizations of [2] to [1] were carried out by contact with silver perchlorate, with trifluoroacetic acid, and even with silica gel. All the isomerizations proceeded under very mild conditions. © 1988, The Chemical Society of Japan. All rights reserved.

DOI： 10.1246/nikkashi.1988.1215

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記述言語：英語  

DOI： 10.1021/ja00248a063

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記述言語：英語   出版者・発行元：CHEMICAL SOC JAPAN  

DOI： 10.1246/bcsj.58.3391

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記述言語：英語   出版者・発行元：AMER CHEMICAL SOC  

DOI： 10.1021/ja00334a070

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：日本語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：日本語   会議種別：口頭発表（招待・特別）  

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記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（指名）  

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記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

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