Cu–guanidine-catalysed asymmetric protoboration of internal 1,3-dienes for one-pot access to chiral homoallylic alcohols

Abstract

The enantioselective protoboration of acyclic internal 1,3-dienes under mild conditions is achieved with a copper–guanidine catalyst. This protocol furnishes α-stereogenic Z-allyl boronates and enables one-pot crotylboration with aldehydes to afford chiral homoallylic alcohols. The stereochemical influence of CC bond geometry and substituent positioning is also elucidated.