Enantioselective Vinyl Radical Addition to Aldehydes via Dual Chromium Catalysis.

Achieving stereocontrol in radical-mediated transformations remains a fundamental challenge, with the enantioselective manipulation of highly reactive vinyl radicals being particularly elusive. Here, we report a dual catalytic system that synergistically merges chiral chromium catalysis with organophotoredox catalysis to address this challenge. This platform enables a three-component, enantioselective 1,2-dialkylation of alkynes, directly converting simple alkyl radical precursors, alkynes, and aldehydes into axially chiral allylic alcohols with high efficiency, diastereoselectivity (up to >20:1 dr), and enantioselectivity (up to 99% ee). Preliminary mechanistic and computational studies support a mechanism involving a photoredox-generated radical cascade, wherein a transient vinyl radical achieves a highly stereoselective carbonyl addition controlled by a chiral chromium catalyst. This work establishes a distinct radical-based disconnection for the concurrent construction of axial and central chirality, providing a catalytic and stereocontrolled alternative to the classical Nozaki-Hiyama-Kishi reaction and opening new avenues for enantioselective radical chemistry.