Diverse C–P Cross-Couplings of Arylsulfonium Salts with Diarylphosphines via Selective C–S Bond Cleavage

Diverse C–P cross-couplings of arylthianthrenium salts with diarylphosphines producing various triarylphosphines via highly selective C–S bond cleavage are reported. In the absence of catalyst, the reaction of arylthianthrenium salts with diarylphosphines undergoes phosphinative ring opening exclusively via the cleavage of an endocyclic C–S bond of a thianthrene skeleton. The use of a palladacycle catalyst under otherwise the same conditions enables the phosphination via the cleavage of an exocyclic C–S bond with significantly higher speed.