Palladium-catalyzed halosulfonylation of alkynes with ionic liquid as the green solvent and halide sources

The first palladium-catalyzed halosulfonylation of alkynes with arylsulfonic acid under aerobic conditions was accomplished. This catalytic protocol provides a straightforward and effective synthetic strategy for the assembly of structurally diverse β-halovinyl sulfones architectures with high atom- and step-economy and exceptional functional group tolerance. Notably, ionic liquid plays a crucial role in this catalytic system, which not only acts as an environmentally friendly solvent, but also provides the halide source. In the presence of 1 ​mol % of IPr-Pd-Cin-Cl as the catalyst, a wide range of terminal alkynes and internal alkynes could be excellently tolerated. Particularly, the developed catalytic system could be recycled up to five times and reused without significant loss of catalytic activity.