Catalyst-Free System for Reductive Addition of Terminal Alkynes via 2,2′-dithiosalicylic Acid in Water

Green, practical, and efficient hydrothiolation of 2,2′-dithiosalicylic acid to terminal alkynes was found to proceed smoothly in water under mild reaction conditions with moderate to good yields. The use of metal catalysts and toxic solvents was avoided, and good to excellent stereoselectivity and regioselectivity were obtained. Herein, the reaction conditions and regioselectivity are discussed, and a preliminary reaction mechanism is proposed. Hydrothiolation of 2,2′-dithiosalicylic acid to terminal alkynes proceeded in water under mild reaction conditions with moderate to good yields.