Efficient and Convenient Synthesis of β-Vinyl Sulfides in Nickel-Catalyzed Regioselective Addition of Thiols to Terminal Alkynes under Solvent-Free Conditions

A new nanosized catalytic system has been developed for convenient preparation of β-vinyl sulfides H2CC(SAr)R with high yields (79−98%) and excellent selectivity (>98:2). Inexpensive and easily available Ni(acac)2 was used as catalyst precursor. Solvent-free conditions were combined with high atom efficiency of the ArSH addition reaction to terminal alkynes (HC⋮C−R) in order to create an environmentally friendly synthetic procedure. The mechanistic study has indicated that catalytic reaction takes place under heterogeneous conditions with alkyne insertion into the Ni−S bond as a key step.