Synthesis of Cyclohexanones by a Tandem Photocatalyzed Annulation

The rapid synthesis of cyclic scaffolds is of high importance to the chemistry community. Strategies for the convergent synthesis of substi-tuted carbocycles and heterocycles remain underexplored despite the plethora of applications that these cyclic motifs have in the phar-maceutical and materials industries. Reported herein is a tandem carbene and photoredox-catalyzed process for the convergent synthesis of substituted cycloalkanones via a formal [5+1] cycloaddition. Featuring two distinct photoredox cycles and a novel α-oxidation of ben-zylic ketones, this reaction offers a mild approach to construct two contiguous C–C bonds and eliminates the need for strong bases or expensive metal catalysts. The utility of this method is highlighted through various product diversification reactions that allow access to a range of important cyclic scaffolds.