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.