Metallaphotoredox Perfluoroalkylation of Organobromides
作者:Xiangbo Zhao、David W. C. MacMillan
DOI:10.1021/jacs.0c09977
日期:2020.11.18
Ruppert-Prakash type reagents (TMSCF3, TMSC2F5, and TMSC3F7) are readily available, air-stable, and easy-to-handle fluoroalkyl sources. Herein, we describe a mild, copper-catalyzed cross-coupling of these fluoroalkyl nucleophiles with aryl and alkyl bromides to produce a diverse array of trifluoromethyl, pentafluoroethyl, and heptafluoropropyl adducts. This light-mediated transformation proceeds via
A radical approach to the copper oxidative addition problem: Trifluoromethylation of bromoarenes
作者:Chip Le、Tiffany Q. Chen、Tao Liang、Patricia Zhang、David W. C. MacMillan
DOI:10.1126/science.aat4133
日期:2018.6
Arenes get a light boost onto copper Insertion of palladium into an aryl halide bond is the first step in numerous variants of cross-coupling chemistry used to make carbon-carbon bonds. Copper is an appealing alternative catalyst for such reactions because of its abundance and downstream reactivity profile. However, this preliminary step, termed oxidative addition, is often prohibitively slow for the
A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles
作者:Lucia Veltri、Roberta Amuso、Marzia Petrilli、Corrado Cuocci、Maria A. Chiacchio、Paola Vitale、Bartolo Gabriele
DOI:10.3390/molecules26082318
日期:——
A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl2-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH2Cl2, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be
提出了一种新的多环杂环的简单方法,即1 H-苯并[4,5]咪唑并[1,2- c ] [1,3]恶嗪-1-酮。它是基于的ZnCl 2促进的脱保护6-内-挖的heterocyclization Ñ -Boc-2- alkynylbenzimidazoles温和的条件下(CH 2氯2,40℃下3小时)。锌中心起双重作用,因为它促进Boc脱保护(形成叔叔-丁基碳正离子,可被带有亲核基团的底物捕获)并激活氨基甲酸酯基团朝分子内亲核进攻的三键。代表性产品的结构已通过X射线衍射分析确认。
Metallaphotoredox Difluoromethylation of Aryl Bromides
作者:Vlad Bacauanu、Sébastien Cardinal、Motoshi Yamauchi、Masaru Kondo、David F. Fernández、Richard Remy、David W. C. MacMillan
DOI:10.1002/anie.201807629
日期:2018.9.17
strategy for the difluoromethylation of arylbromides by metallaphotoredox catalysis. Bromodifluoromethane, a simple and commercially available alkyl halide, is harnessed as an effective source of difluoromethyl radical by silyl‐radical‐mediated halogen abstraction. The merger of this fluoroalkyl electrophile activation pathway with a dual nickel/photoredox catalytic platform enables the difluoromethylation