Enantioselective Copper-Catalyzed Defluoroalkylation Using Arylboronate-Activated Alkyl Grignard Reagents
作者:Minyan Wang、Xinghui Pu、Yunfei Zhao、Panpan Wang、Zexian Li、Chendan Zhu、Zhuangzhi Shi
DOI:10.1021/jacs.8b04902
日期:2018.7.25
A copper-catalyzed system has been introduced for the enantioselective defluoroalkylation of linear 1-(trifluoromethyl)alkenes through C-F activation to synthesize various gem-difluoroalkenes as carbonyl mimics. For the first time, arylboronate-activated alkylGrignardreagents were uncovered in this cross-coupling reaction. Mechanistic studies confirmed that the tetraorganoborate complexes generated
A visible-light-induced decarboxylative trifluoromethylation of alpha,beta-unsaturatedcarboxylicacids, which uses the Togni reagent as the CF3 source is disclosed. The corresponding trifluoromethylated alkenes were obtained in moderate to high yields with excellent functional group tolerance at ambient temperature. Preliminary mechanistic analyses suggest a radical-type mechanism.
An efficient method for the iron(III) porphyrincatalyzed olefination of various aldehydes with 2,2,2‐trifluorodiazoethane (CF3CHN2) under neutral conditions has been developed. This reaction is an important supplement to the synthetic applications of CF3CHN2.
(<i>Z</i>)- or (<i>E</i>)-Selective Hydrogenation of Potassium (3,3,3-Trifluoroprop-1-yn-1-yl)trifluoroborate: Route to Either Isomer of β-Trifluoromethylstyrenes
vinylborate in >98% purity is described. The initially formed (Z)-isomer of the alkene is transformed to the (E)-isomer with time, irrespective of the catalyst used; coupling with bromo- and iodoarenes provides a variety of (Z)- or (E)-β-trifluoromethylstyrenes. Also, a safe synthesis of the alkynyltrifluoroborate from HFC-245fa and BF3·OEt2 has been described.