Cu-Promoted Divergent Phosphination of Alkynylsulfonium Salts with Diarylphosphines.

An efficient copper-promoted divergent phosphination of alkynylsulfonium salts 1 with secondary diarylphosphines 2 that tolerates a wide range of functional groups under mild conditions is reported. The use of excess alkynyl dibenzothiophenium salts ( 1 / 2 > 1, mole ratio) enables the phosphination to deliver alkynyl monophosphine products via a C(sp)-P cross-coupling in good to high yields, while the use of excess secondary diarylphosphines ( 1 / 2 < 0.5, mole ratio) leads to a type of cis -ethenyl bisphosphine products via sequential stereoselective double phosphination.