Dual Cobalt/Organophotoredox Catalysis for Diastereo- and Regioselective 1,2-Difunctionalization of 1,3-Diene Surrogates Creating Quaternary Carbon Centers

The synthesis of compounds having quaternary carbon centers through a catalytic stereo- and regioselective difunctionalization of 2-substituted 1,3-dienes remains elusive. Here, we present a dual Co/photoredox-catalyzed cascade approach that addresses this challenge using modular vinyl cyclic carbonates functioning as masked 2-aryl-1,3-diene surrogates. The latter species are conveniently prepared in situ and converted into nucleophilic Co­(allyl) intermediates that are intercepted by aldehydes to afford homoallylic alcohols with ample scope in reaction partners. The developed protocol marks a significant step forward in the use of structurally versatile 1,3-dienes and their catalytic 1,2-hydroalkylation and 1,2-dicarbofunctionalization.