Selective 1,2‐Carboimination of Isothiocyanates to Access <i>S</i>‐Substituted Isothioureas via Energy Transfer Catalysis

Abstract Herein, we introduce a novel method for the synthesis of S ‐substituted isothiourea compounds via the selective 1,2‐carboimination between oxime esters as bifunctional reagents and the C=S bond of isothiocyanates under visible‐light catalysis. This approach deviates from conventional methods by precisely modulating the substrate electronics to selectively functionalize the C=S bond of isothiocyanates over the C=N bond, eliminating the need for strong bases and high temperatures and bypassing the formation of thiourea intermediates. Consequently, this protocol enables the efficient one‐step synthesis of S ‐alkyl isothioureas, with featuring mild reaction conditions, operational simplicity and broad substrate scope.