Fragment Couplings via CO2 Extrusion-Recombination: Expansion of a Classic Bond-Forming Strategy via Metallaphotoredox.

In this study we demonstrate that molecular fragments, which can be readily coupled via a simple, in situ RO-C═OR bond-forming reaction, can subsequently undergo metal insertion-decarboxylation-recombination to generate Csp(2)-Csp(3) bonds when subjected to metallaphotoredox catalysis. In this embodiment the conversion of a wide variety of mixed anhydrides (formed in situ from carboxylic acids and acyl chlorides) to fragment-coupled ketones is accomplished in good to high yield. A three-step synthesis of the medicinal agent edivoxetine is also described using this new decarboxylation-recombination protocol.