Cobalt-catalyzed hydrothiolation of alkynes for the diverse synthesis of branched alkenyl sulfides

Abstract

Alkenyl sulfides have gained increasing prominence in medicinal chemistry and materials. Hydrothiolation of alkynes for the diverse synthesis of alkenyl sulfides is an appealing method. Herein, we report a cobalt-catalyzed Markovnikov hydromethylthiolation of alkynes to afford branched alkenyl methylsulfanes with good yields and high regioselectivity. This method also enables the diverse synthesis of branched alkenyl sulfides. The reaction shows good functional group tolerance and could be scaled up. The mechanistic studies including control experiments, deuterium-labeling experiments, and Hammett plot indicated alkynes insertion followed by electrophilic thiolation pathway. Branched alkenyl sulfides are useful moieties in synthesis and materials. Here, the authors disclose a hydromethylthiolation of alkynes via cobalt hydride catalysis, resulting in Markovnikov regioselectivity, proceeding via electrophilic thiolation.

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