Palladium-Catalyzed Cleavage of P-C Bonds in Quaternary Phosphonium Salts and Its Applications to Organic Synthesis

Phosphonium salts, PPh4I and PMePh3I, oxdatively add to Pd(methyl acrylate)(PMePh2)2 to give trans-[PdPhI(PMePh2)2] in moderate yields with cleavage of the P-phenyl bond. Conversely thermolysis of trans-PdPhIL2 (L = PMePh2 and PPh3) reductively eliminates PMePh3I and PPh4I, respectively. Application of the P-C bond cleavage process in phosphonium salts to olefination, carbonylation and hydrogenation reactions has been explored.