- Radical hydroalkylation and hydroacylation of alkenes by the use of benzothiazoline under thermal conditions
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The hydroalkylation and hydroacylation of electrondeficient alkenes proceeded smoothly by using benzothiazoline derivatives as radical-transfer reagents under thermal conditions without light irradiation or any additive. Both benzyl and benzoyl moieties were transferred efficiently.
- Akiyama, Takahiko,Uchikura, Tatsuhiro,Toda, Mitsuhiro,Mouri, Toshiki,Fujii, Tatsuya,Moriyama, Kaworuko,Ibanez, Ignacio
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p. 12715 - 12723
(2020/11/09)
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- Catalytic Acceptorless Dehydrogenation of Aliphatic Alcohols
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We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centered radical with a nickel catalyst, and β-hydride elimination. The reaction proceeded in high yield under mild conditions without producing side products (except H2 gas) from various alcohols, including sterically hindered alcohols, a steroid, and a pharmaceutical derivative. This catalyst system also promoted acceptorless cross-dehydrogenative esterification from aldehydes and alcohols through hemiacetal intermediates.
- Fuse, Hiromu,Mitsunuma, Harunobu,Kanai, Motomu
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supporting information
p. 4493 - 4499
(2020/03/05)
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- Visible-Light-Mediated Regioselective Allylation, Benzylation, and Silylation of Methylene-Malononitriles via Photoredox-Induced Radical Cation Fragmentation
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Visible-light-mediated regioselective allylation, benzylation, and silylation of methylene-malononitriles using allylic/benzylic silane and disilane reagents have been developed, delivering the corresponding allylated, benzylated, and silylated products i
- Liu, Rongfang,Chia, Shane Pui Mun,Goh, Yi Yiing,Cheo, Han Wen,Fan, Binbin,Li, Ruifeng,Zhou, Rong,Wu, Jie
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p. 1459 - 1465
(2019/08/21)
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- Benzothiazolines as radical transfer reagents: Hydroalkylation and hydroacylation of alkenes by radical generation under photoirradiation conditions
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Novel radical transfer reagents under photoirradiation conditions were developed by the use of benzothiazoline derivatives. These reagents enabled both hydroalkylation and hydroacylation of alkenes under neutral conditions at ambient temperature without a
- Uchikura, Tatsuhiro,Moriyama, Kaworuko,Toda, Mitsuhiro,Mouri, Toshiki,Ibá?ez, Ignacio,Akiyama, Takahiko
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supporting information
p. 11171 - 11174
(2019/09/30)
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- A Redox-Active Nickel Complex that Acts as an Electron Mediator in Photochemical Giese Reactions
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We report a simple protocol for the photochemical Giese addition of C(sp3)-centered radicals to a variety of electron-poor olefins. The chemistry does not require external photoredox catalysts. Instead, it harnesses the excited-state reactivity of 4-alkyl-1,4-dihydropyridines (4-alkyl-DHPs) to generate alkyl radicals. Crucial for reactivity is the use of a catalytic amount of Ni(bpy)32+ (bpy=2,2′-bipyridyl), which acts as an electron mediator to facilitate the redox processes involving fleeting and highly reactive intermediates.
- van Leeuwen, Thomas,Buzzetti, Luca,Perego, Luca Alessandro,Melchiorre, Paolo
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supporting information
p. 4953 - 4957
(2019/03/13)
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- Eosin Y as a Direct Hydrogen-Atom Transfer Photocatalyst for the Functionalization of C?H Bonds
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Eosin Y, a well-known economical alternative to metal catalysts in visible-light-driven single-electron transfer-based organic transformations, can behave as an effective direct hydrogen-atom transfer catalyst for C?H activation. Using the alkylation of C?H bonds with electron-deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y-based photocatalytic hydrogen-atom transfer strategy is promising for diverse functionalization of a wide range of native C?H bonds in a green and sustainable manner.
- Fan, Xuan-Zi,Rong, Jia-Wei,Wu, Hao-Lin,Zhou, Quan,Deng, Hong-Ping,Da Tan, Jin,Xue, Cheng-Wen,Wu, Li-Zhu,Tao, Hai-Rong,Wu, Jie
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supporting information
p. 8514 - 8518
(2018/07/14)
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- Metal-free direct alkylation of unfunctionalized allylic/benzylic sp3 C-H bonds: Via photoredox induced radical cation deprotonation
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Despite notable recent efforts, a catalytic and convenient strategy for the direct alkylation of unactivated allylic or benzylic sp3 C-H bonds remains a formidable challenge facing the synthesis community. We herein report an unprecedented allylic/benzylic alkylation using only an organo-photoredox catalyst, which enables coupling of a broad scope of alkenes/arenes and electron-deficient alkenes in an atom-and redox-economic manner. A photoredox induced alkene/arene radical cation deprotonation is proposed to smoothly generate the key allylic and benzylic radical intermediates. It represents the first C-C bond formation via radical cation deprotonation under visible light conditions. The resulting products can be easily scaled up and directly converted to γ,δ-unsaturated or α,β-diaryl-acids,-esters,-amides,-pyrazoles,-isoxazoles, as well as lactones, which enables this mild and selective sp3 C-H alkylation to rapidly access complex bioactive molecules.
- Zhou, Rong,Liu, Haiwang,Tao, Hairong,Yu, Xingjian,Wu, Jie
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p. 4654 - 4659
(2017/07/10)
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- A Novel Photoalkylation of Electron-deficient Alkenes by Use of Organotin Compounds via Photoinduced Electron Transfer
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Irradiation of 1-aryl-2,2-dicyanoethenes and tetraalkylstannanes in propionitrile in the presence of phenanthrene afforded regioselectively 1-alkyl-1-aryl-2,2-dicyanoethanes in good yields.
- Mizuno, Kazuhiko,Nakanishi, Kazuhisa,Tachibana, Atsushi,Otsuji, Yoshio
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p. 344 - 345
(2007/10/02)
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- Dual Regioselectivity in the Photoallylation of Electron-Deficient Alkenes by Allylic Silanes
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The photoreaction of 1-aryl-2,2-dicyanoethenes with allylic silanes in the presence of phenanthrene gave 4-aryl-5,5-dicyano-1-pentenes in high yields.In this photoreaction, the allylic groups were introduced regioselectively at the β-position to cyano gro
- Mizuno, Kazuhiko,Ikeda, Munehiro,Otsuji, Yoshio
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p. 1507 - 1510
(2007/10/02)
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