Pd(II)-Catalyzed Enantioselective C-H Olefination and Photoregulation of Sterically-Hindered Diarylethenes

Abstract

Sterically-hindered diarylethenes with intrinsic chirality have shown great potential in chiral signal regulation, light-controlled liquid crystals (LCs), etc. Their unique enantiospecific phototransformation between axial chirality of ring-open isomer and central chirality of ring-closed isomer can break through the bottleneck of the interference between multiple chiral centers in traditional chiral diarylethenes. However, these intrinsic chiral diarylethenes require necessary chiral resolution through preparative chiral HPLC, typically resulting in limited separation efficiency and production scale. Here, we present an enantioselective olefination strategy to directly construct intrinsic chiral diarylethenes from a prochiral sterically-hindered diarylethene, achieving high yields and enantioselectivity. The resulting isomers can be further decorated by incorporating mesogenic units, and the derivatives enable the successful reversible photoregulation of blue, green, and red reflection colors of LC with excellent thermal stability, fatigue resistance, and little texture disorderliness, demonstrating the practical application potential of direct enantioselective olefination in photoregulation with intrinsic chiral diarylethenes.