A site-selective amination catalyst discriminates between nearly identical C-H bonds of unsymmetrical disubstituted alkenes.

Abstract

C–H activation reactions enable chemists to unveil new retrosynthetic disconnections and streamline conventional synthetic approaches. A longstanding challenge in C–H activation is the inability to distinguish electronically and sterically similar C–H bonds. Although numerous synergistic combinations of transition-metal complexes and chelating directing groups have been utilized to distinguish C–H bonds, undirected regioselective C–H functionalization strategies remain elusive. Herein, we report a regioselective C–H activation/amination reaction of various unsymmetrical dialkyl-substituted alkenes. The regioselectivity of C–H activation is correlated to the electronic properties of allylic C–H bonds indicated by the corresponding 1JCH coupling constants. A linear relationship between the difference of 1JCH coupling constants of the two competing allylic C–H bonds (Δ1JCH) and the C–H activation barriers (ΔΔG‡) has also been determined.