Catalytic regio- and stereoselective silicon–carbon bond formations on unsymmetric gem-difluorocyclopropenes by capture of silyl metal species

Abstract

We report herein that a highly regioselective silicon–carbon bond-forming silylation of unsymmetric gem-difluorocyclopropenes based on Si–C or Si–B bond cleavage of organosilicon reagents was achieved using palladium or copper catalysis through the capture of in situ formed silyl metal intermediates. These reactions effectively deliver structurally diverse difluorocyclopropanes, including sila-difluorobicyclo[4.1.0]heptanes and silyl gem-difluorocyclopropanes, in a stereoselective manner, in which two types of silicon-containing gem-difluorocyclopropanes can be achieved in good yields with high regioselectivity, and silyl gem-difluorocyclopropanes can be obtained with excellent enantioselectivity (up to 97% ee) in the presence of a chiral TADDOL-derived phosphoramidite ligand.