Enantioselective Synthesis of Both Axially and Planar Chiral Ferrocenes via Axial-to-Planar Diastereoinduction

Org Lett. 2022 Oct 14;24(40):7294-7299. doi: 10.1021/acs.orglett.2c02707. Epub 2022 Sep 30.

Abstract

Ferrocenes with planar chirality have emerged as an important class of scaffolds for ligands in asymmetric catalysis; however, ferrocene molecules with polychiral structures have not been well explored. Herein, both axially and planar chiral ferrocenes were synthesized via palladium/chiral norbornene cooperative catalysis and axial-to-planar diastereoinduction. In this work, chiral norbornene was used to stereoselectively control the aromatic axial chirality, and further selectivity induced C(sp2)-H activation for ferrocene planar chirality. Based on density functional theory calculations, the catalytic model of chiral norbornene with the substrate and the axial-to-planar diastereoinduction process were confirmed.