A5009551422- Radical Photochemical Reactions
- Oxidative Organic Chemistry Reactions
- Catalytic C–H Functionalization Methods
- Fluorine in Organic Chemistry
- Sulfur-Based Synthesis Techniques
- Organic Chemistry Cycloaddition Reactions
- Cyclopropane Reaction Mechanisms
- Synthetic Organic Chemistry Methods
- Chemical Synthesis and Reactions
- Asymmetric Synthesis and Catalysis
- Photochemistry and Electron Transfer Studies
- Synthesis of Organic Compounds
- Photochromic and Fluorescence Chemistry
- Chemical Synthesis and Analysis
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Supramolecular Chemistry and Complexes
- Synthesis and Reactions of Organic Compounds
- Coordination Chemistry and Organometallics
- Porphyrin and Phthalocyanine Chemistry
- Synthesis and Biological Evaluation
- Organic and Inorganic Chemical Reactions
- Synthesis and Catalytic Reactions
- Synthesis of heterocyclic compounds
- Synthesis and Reactivity of Sulfur-Containing Compounds
Niigata University
2014-2024
Graduate School USA
2015-2021
Niigata University Medical and Dental Hospital
2020
Institute for Rheumatic Diseases (Japan)
2018
Tohoku University
1982-2005
University of Pittsburgh
1993-1994
University of Maryland, College Park
1987-1989
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditive and solvent effects on samarium diiodide reductions: the of water DMPUEietsu Hasegawa Dennis P. CurranCite this: J. Org. Chem. 1993, 58, 18, 5008–5010Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://pubs.acs.org/doi/10.1021/jo00070a046https://doi.org/10.1021/jo00070a046research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron-transfer-induced photoadditions of the silyl amine, Et2NCH2SiMe3, to .alpha.,.beta.-unsaturated cyclohexenones. Dual reaction pathways based on ion pair-selective cation-radical chemistryEietsu. Hasegawa, Wei. Xu, Patrick S. Mariano, Ung Chan. Yoon, and Jin Uk. KimCite this: J. Am. Chem. Soc. 1988, 110, 24, 8099–8111Publication Date (Print):November 1, 1988Publication History Published online1 May 2002Published inissue 1 November...
Triarylamine-substituted benzimidazoliums (BI+-PhNAr2), new electron donor-acceptor dyad molecules, were synthesized. Their photocatalytic properties for reductive organic transformations explored using absorption and fluorescence spectroscopy, redox potential determinations, density functional theory calculations, transient reduction reactions of selected substrates. The results show that irradiation BI+-PhNAr2 promotes photoinduced intramolecular transfer to form a long-lived (∼300 μs)...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExploratory study on photoinduced single electron transfer reactions of .alpha.,.beta.-epoxy ketones with aminesEietsu Hasegawa, Kenyuki Ishiyama, Takaaki Horaguchi, and Takahachi ShimizuCite this: J. Org. Chem. 1991, 56, 4, 1631–1635Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/jo00004a052https://doi.org/10.1021/jo00004a052research-articleACS...
In the photoreaction of benzophenones with 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI), benzhydrols were major products. Addition H2O accelerated reaction no change in product distribution, while AcOH, PhOH, and metal salts such as LiClO4 Mg(ClO4)2 effective additives to produce benzpinacols. contrast, benzpinacols exclusively formed regardless solvent additive reactions 2-(o-hydroxyphenyl)-1,3-dimethylbenzimidazoline (o-HPDMBI). These observations are consistent hypothesis that DMPBI•+...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoadditions of ethers, thioethers, and amines to 9,10-dicyanoanthracene by electron transfer pathwaysEietsu Hasegawa, Martha A. Brumfield, Patrick S. Mariano, Ung Chan YoonCite this: J. Org. Chem. 1988, 53, 23, 5435–5442Publication Date (Print):November 1, 1988Publication History Published online1 May 2002Published inissue 1 November 1988https://pubs.acs.org/doi/10.1021/jo00258a007https://doi.org/10.1021/jo00258a007research-articleACS...
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 well desulfonylation reactions in which 1,3-dimethyl-2-phenylbenzimidazoline (Ph-BIH) cooperates with electron hydrogen atom donor. Significant solvent effects on reaction progress were discovered, specific solvation toward imidazolium moieties proposed.
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 absorbing, electron hydrogen atom donor, household white light-emitting diode source. The transforms various N-sulfonylamide -amine substrates to desulfonylated products moderate excellent yields. observation that the fluorescence 1-methyl-2-naphthoxy anion is efficiently quenched by suggests mechanism...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel electron-transfer photocyclization reactions of .alpha.-silyl amine .alpha.,.beta.-unsaturated ketone and ester systemsWei Xu, Yoon T. Jeon, Eietsu Hasegawa, Ung C. Yoon, Patrick S. MarianoCite this: J. Am. Chem. Soc. 1989, 111, 1, 406–408Publication Date (Print):January 1989Publication History Published online1 May 2002Published inissue 1 January 1989https://doi.org/10.1021/ja00183a081RIGHTS & PERMISSIONSArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron-transfer photochemistry of .alpha.-silylamine-cyclohexenone systems. Medium effects on reaction pathways followedUng Chan Yoon, Jin Uk Kim, Eietsu Hasegawa, and Patrick S. MarianoCite this: J. Am. Chem. Soc. 1987, 109, 14, 4421–4423Publication Date (Print):July 1, 1987Publication History Published online1 May 2002Published inissue 1 July 1987https://pubs.acs.org/doi/10.1021/ja00248a063https://doi.org/10.1021/ja00248a063research-articleACS...
Abstract The intermolecular aromatic substitution of N , ‐disubstituted anilines with diazo esters is achieved under mild conditions in the presence a catalytic amount copper(II) triflate (up to 89 % yield). scope and limitations regarding substrates, esters, ligands this reaction are described.
An unprecedented photocatalytic system consisting of benzimidazolium aryloxide betaines (BI+-ArO-) and stoichiometric hydride reducing reagents was developed for carrying out desulfonylation reactions N-sulfonyl-indoles, -amides, -amines, α-sulfonyl ketones. Measurements absorption spectra cyclic voltammograms as well density functional theory (DFT) calculations were carried to gain mechanistic information. In the catalytic system, visible-light-activated benzimidazoline aryloxides...
Photoreaction of trans-1-(4-cyanophenyl)-3-phenyl-2,3-epoxy-1-propanone (trans-4'-cyanochalcone epoxide) with various electron donors was studied. Irradiation this epoxy ketone amines produced 1-(4-cyanophenyl)-3-phenyl-1,3-propanedione and 1-(4-cyanophenyl)-3-hydroxy-3-phenyl-1-propanone in ratios depending on the kinds amine solvent used. A reaction mechanism involving an cation radical-assisted rearrangement anion radical proposed to be most consistent marked change yield beta-diketone....
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemically and thermally induced free-radical reactions of .alpha.,.beta.-epoxy ketones with tributyltin hydride: selective C.alpha.-O bond cleavage oxiranylmethyl radicals derived from ketonesEietsu Hasegawa, Kenyuki Ishiyama, Tomoyasu Kato, Takaaki Horaguchi, Takahachi Shimizu, Shoji Tanaka, Yoshiro YamashitaCite this: J. Org. Chem. 1992, 57, 20, 5352–5359Publication Date (Print):September 1, 1992Publication History Published online1 May...
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 for PET induced, reductive transformations of various organic substrates, including α,β-epoxy ketones, the olefin tethered 2-bromomethyl-1-tetralone, o-allyloxy-iodobenzene, well deprotection reactions dodecyl-2-benzoylbenzoate...
Samarium diiodide promoted reaction of various alpha-bromomethyl cycloalkanones, followed by subsequent treatment with trimethylsilyl chloride, leads to the production cyclopropyl silyl ethers embedded in bicyclo[m.1.0]alkane frameworks. Treatment oxidative electron-transfer reagents, such as Fe(III), Ce(IV), and Mn(III) salts, generates ring-expanded ketones that convert cyclic conjugated enones moderate good yields. In addition, reduction-oxidation sequences can be successfully performed...
[5]Catenanes were synthesized by olefin metathesis dimerization.
The syntheses of [2]- and [3]catenanes by olefin metathesis oxidative acetylide coupling have been studied in detail. Pseudorotaxanes that were obtained mixing crown ether ammonium salts containing two terminal reactive end-groups converted to [3]catenane. Their yields influenced not only the chain length but also concentration salts. strain energies [2]catenane responsible for formation [2]catenane.