Palladium-Catalyzed Desulfitative Conjugate Addition of Aryl Sulfinic Acids and Direct ESI-MS for Mechanistic Studies

A new and efficient method for palladium(II) catalytic desulfitative conjugate addition of arylsulfinic acids with alpha,beta-unsaturated carbonyl compound has been developed. The key reacting intermediates including aryl Pd(II) sulfinic intermediate, aryl Pd(II), and C=O-Pd complexes were captured by ESI-MS/MS, which provide new experimental evidence for the understanding of addition mechanism.