irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)*/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
Organophotocatalytic Arene Functionalization: C–C and C–B Bond Formation
作者:Da Seul Lee、Chung Soo Kim、Naila Iqbal、Gyeong Su Park、Kyung-sun Son、Eun Jin Cho
DOI:10.1021/acs.orglett.9b03877
日期:2019.12.20
developed in the presence of an organophotosensitizer, 3,7-di([1,1'-biphenyl]-4-yl)-10-(4-(trifluoromethyl)phenyl)-10H-phenoxazine that has highly negative reduction potential at its photoexcited state. The developed reaction conditions are mild and allow the intermolecular C-C bond formation of the generated aryl radical with electron-rich (hetero)arenes and C-B bond formation with bis(pinacolato)diboron
available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radicalreactions.
Polysulfide Anions as Visible Light Photoredox Catalysts for Aryl Cross-Couplings
作者:Haoyu Li、Xinxin Tang、Jia Hao Pang、Xiangyang Wu、Edwin K. L. Yeow、Jie Wu、Shunsuke Chiba
DOI:10.1021/jacs.0c11968
日期:2021.1.13
we disclose the use of polysulfide anions as visible light photoredox catalysts for aryl cross-coupling reactions. The reaction design enables single-electron reduction of aryl halides upon the photoexcitation of tetrasulfide dianions (S42-). The resulting aryl radicals are engaged in (hetero)biaryl cross-coupling, borylation, and hydrogenation in a redox catalytic regime involving S4• -/S42- and S3• -/S32-
Aminoalkyl radicals as halogen-atom transfer agents for activation of alkyl and aryl halides
作者:Timothée Constantin、Margherita Zanini、Alessio Regni、Nadeem S. Sheikh、Fabio Juliá、Daniele Leonori
DOI:10.1126/science.aba2419
日期:2020.2.28
Amines as a gateway to alkyl radicals In recent years, photoredox catalysis driven by blue light has often been used to oxidize carbon centers adjacent to nitrogen. Constantin et al. now show that these aminoalkyl radicals can, in turn, conveniently strip iodine atoms from a variety of alkyl carbons. The new alkyl radicals that result readily undergo deuteration and couplings such as alkylation, allylation