Visible-light-induced three-component radical cascade 1,2-dialkylation of alkenes to access alcohols†

Visible-light-mediated 1,2-dicarbofunctionalization of alkenes provides a powerful tool for the synthesis of structurally complicated and diverse molecules from simple precursors in one step. In this work, photo-catalyzed three-component 1,2-alkylation of alkenes with alkylboronic pinacol esters (APEs) and aldehydes has been accomplished. This transition-metal-free protocol provided a clean and efficient way to access secondary alcohols, with wide substrate scope compatibility and good functional group tolerance, and it allowed a variety of alkenes, APEs and aldehydes to be transformed to the desired products in moderate to good yields under metal-free conditions. Mechanism studies disclosed that this transformation may involve a radical addition and radical–radical cross-coupling process.