Reaction Behavior of Quinone Carbene in C-S Bond Construction: From Chemical Mechanism to Catalyst Regulation

Organic molecules containing C-S bonds have crucial application value in the field of medicinal chemistry and functional materials. However, traditional synthetic methods, such as thiol nucleophilic substitution, are often restricted by some factors, for instance, the reaction conditions are relatively harsh, the functional group tolerance is not good, and there is a risk of oxidation of sulfur atoms. The quinone-mediated C-S bond construction method provides a new approach for the gentle and efficient direct construction of C-S bonds. Its core mechanism is as follows: In this study, transition metals and diazoquinones are combined to catalyze the formation of highly active carbon intermediates. Due to their relatively strong electrophilicity, these intermediates can directly react with sulfides to form C-S bonds. The reaction requires no substrate preactivation and can proceed at room temperature under an inert atmosphere, effectively avoiding side reactions such as sulfur oxidation. Reaction conditions including catalyst type, solvent system, and reaction temperature affect the chemoselectivity and regioselectivity of the products. This study aims to overcome the limitation of poor regioselectivity control in traditional thiol nucleophilic substitution reactions, provide efficient and green new strategies for the precise synthesis of sulfur-containing functional molecules, and further expand the application potential of carbene reactions in the synthesis of complex molecules.