Organocatalytic olefin C–H functionalization for enantioselective synthesis of atropisomeric 1,3-dienes

The availability of structurally and stereochemically diverse chemical scaffolds is important to support continual development of drug discovery, functional materials and asymmetric synthesis. Axially chiral 1,3-dienes, particularly acyclic ones, are potentially valuable yet underutilized skeletons due to concerns about chiral stability and the absence of suitable synthetic conditions. Here we show an organocatalytic strategy for the direct functionalization of alkenyl C–H bonds, enabling the challenging atroposelective construction of a broad range of acyclic chiral 1,3-dienes in a modular manner. Intensive studies on the reaction mechanism show that the current strategy not only bypasses the traditional indirect process for olefinic C–H functionalization but also represents a departure from transition-metal-catalysed C( sp 2 )–H activation. These findings are expected to open avenues for research on olefin chemistry and to inspire investigation into the organocatalytic activation of other inert structures.