Bifunctional Chiral Electrocatalysts Enable Enantioselective α-Alkylation of Aldehydes

Angew Chem Int Ed Engl. 2024 Sep 23;63(39):e202401355. doi: 10.1002/anie.202401355. Epub 2024 Aug 22.

Abstract

Herein, we describe an innovative approach to the asymmetric electrochemical α-alkylation of aldehydes facilitated by a newly designed bifunctional chiral electrocatalyst. The highly efficient bifunctional chiral electrocatalyst combines a chiral aminocatalyst with a redox mediator. It plays a dual role as a redox mediator for electrooxidation, while simultaneously providing remarkable asymmetric induction for the stereoselective α-alkylation of aldehydes. Additionally, this novel catalyst exhibits enhanced catalytic activity and excellent stereoselective control comparable to conventional catalytic systems. As a result, this strategy provides a new avenue for versatile asymmetric electrochemistry. The electrooxidation of diverse phenols enables the C-H/C-H oxidative α-alkylation of aldehydes in a highly chemo- and stereoselective fashion. Detailed mechanistic studies by control experiments and cyclic voltammetry analysis demonstrate possible reaction pathways and the origin of enantio-induction.

Keywords: bifunctional chiral electrocatalyst; bifunctional electrolysis; electrosynthesis; enantioselectivity; redox mediator.