Ligand-Controlled Regiodivergent Thiocarbonylation of Alkynes toward Linear and Branched α,β-Unsaturated Thioesters

Thiocarbonylation of alkynes offers an ideal procedure for the synthesis of unsaturated thioesters. A robust ligand-controlled regioselective thiocarbonylation of alkynes is developed. Utilizing boronic acid and 5-chlorosalicylic acid as the acid additive to in situ form 5-chloroborosalicylic acid (5Cl-BSA), and bis(2-diphenylphosphinophenyl)ether (DPE-phos) as the ligand, linear alpha,beta-unsaturated thioesters were produced in a straightforward manner. Switching the ligand to tri(2-furyl)phosphine can turn the reaction selectivity to give branched products. Remarkably, this approach also represents the first example on thiocarbonylation of internal alkynes.

Automated summary

Thiocarbonylation of alkynes offers a versatile method for the synthesis of unsaturated thioesters, with the possibility of controlling the product structure by using different ligands and acid additives. This approach also demonstrates the first example of thiocarbonylation of internal alkynes.