Rhodium-Catalyzed Asymmetric Arylation/Defluorination of 1-(Trifluoromethyl)alkenes Forming Enantioenriched 1,1-Difluoroalkenes

摘要

The reaction of 1-(trifluoromethyl)alkenes (CF_3CH=CHR) with arylboroxines (ArBO)_3 in the presence of a chiral diene-rhodium catalyst gave high yields of chiral 1,1-difluoroalkenes (CF_2=CHC*HArR) with high enantioselectivity (≥95% ee). The reaction is assumed to proceed through β-fluoride elimination of a β,β,β-trifluoroaIkylrhodium intermediate that is generated by arylrhodation of the 1-(trifluoromethyl)alkene.