Synthesis of polymethylene-linked bis(cyclobutane-fused chromanones) mediated by gold-photocatalysis

Abstract

We report an efficient gold-mediated energy transfer photocatalytic method for the synthesis of polymethylene-linked bis(cyclobutane-fused chromanones) from coumarins and dienes, which undergo intermolecular [2+2] photocycloaddition. The transformation proceeds under mild conditions and provides access to structurally complex products in moderate to good yields across a range of substrates. Mechanistic studies support a triplet energy transfer reaction pathway.