Dual Photoredox/Brønsted Base-Catalyzed syn -Alkylcarboxylation of Bicyclo[1.1.0]butanes Using Malonates as Difunctional Reagents

Malonates are widely employed as nucleophilic alkyl precursors in organic synthesis; however, their use as difunctional reagents has largely been unexplored. Herein, we report a mild, regio- and diastereoselective syn-alkylcarboxylation of bicyclo[1.1.0]butanes (BCBs) with malonates, enabled by dual photoredox/Brønsted base catalysis. This method employs malonates as bifunctional reagents and accommodates a broad range of BCB derivatives, delivering cyclobutyl-fused 1,6-diesters in good to excellent yields.