Combined photoredox and carbene catalysis: alkene borocarbonylation via the persistent radical effect

Abstract

Herein, we report a mild and operationally simple dual-catalytic method for the synthesis of β-boryl carbonyl compounds via alkene difunctionalization. Specifically, combining N-heterocyclic carbene catalysis and photocatalysis enables a three-component radical cross-coupling reaction between a wide range of feedstock carboxylic acids, easily prepared NHC-boranes, and readily available alkenes to yield structurally diverse β-boryl carbonyl compounds. Longer lifetime ketyl radicals facilitate efficient boron participation in the coupling through the persistent radical effect. The method could be used to install acyl and borane groups on highly functionalized natural-product-derived compounds without pre-activation in one step and most products show good diastereoselectivity.