Selective 1,2-Carboimination of Isothiocyanates to Access S-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.