Visible <scp>Light‐Mediated</scp> Cobalt and Photoredox <scp>Dual‐Catalyzed</scp> Asymmetric Reductive Coupling for Axially Chiral Secondary Alcohols ^†

Abstract

Comprehensive Summary Secondary alcohols bearing both axial and central chirality comprise attractive biological activity and exhibit excellent chiral induction in asymmetric reactions. However, only very limited asymmetric catalytic approaches were developed for their synthesis. We herein describe visible light‐mediated cobalt‐catalyzed asymmetric reductive Grignard‐type addition of aryl iodides with axially prochiral biaryl dialdehydes leading to the direct construction of axially chiral secondary alcohols. Preliminary mechanistic studies indicate that efficient kinetic recognition of diastereomers might occur for axially prochiral dialdehydes to improve the stereoselectivity, which might open a new avenue for the challenging cascade construction of multiple chiral elements. This protocol features excellent enantio‐ and diastereoselectivity, green and mild conditions, simple operation, and broad substrate scope, providing a modular platform for the synthesis of secondary axially chiral alcohols.