Construction of axial chirality by asymmetric alpha C–H alkenylation of aryl alkenes

Abstract

An asymmetric α-C–H alkenylation of aryl alkenes has been disclosed to provide axially chiral aryl 1,3-dienes, proceeding through six-membered exo-cyclopalladation, assisted by an aldehyde/L-t-leucine derived transient chiral auxiliary. This protocol is successfully applied to a wide range of 2-vinyl benzaldehydes as well as coupling partners bearing sensitive (+)-dehydroabietylamine, geraniol and cholesteryl moieties. The axially chiral carboxylic acid, derived from aldehyde products by oxidation, is proved to be a promising chiral ligand in asymmetric C–H alkylation under Cp*Co(III) catalysis.