Sustainable HandaPhos-ppm Palladium Technology for Copper-Free Sonogashira Couplings in Water under Mild Conditions.

Complexation of ca. 1000 ppm Pd(OAc)2 with the ligand HandaPhos (1-1.5:1) leads to a precatalyst that efficiently mediates Sonogashira couplings in aqueous nanomicelles under very mild conditions. Neither copper nor organic solvent is required in the reaction medium, and the product can be isolated directly from the reaction flask, leaving behind a reaction mixture that can be recycled without additional additives.