Phenoxide-assisted P–C bond cleavage in PdCl 2(PPh 3) 2 under very mild conditions

Abstract

PdCl 2(PPh 3) 2 reacted with NaOAr (Ar = Ph, p-tolyl) at 0 °C to afford PdCl(Ph)(PPh 3) 2, instead of PdCl(OAr)(PPh 3) 2, in 12–16% isolated yields based on Pd. The structure was confirmed by NMR and X-ray crystallography. GC–MS analysis of the reaction solution revealed that OPPh 2(OAr), OPPh(OAr) 2, and OP(OAr) 3 are formed, while NMR studies indicated that PdCl(Ph)(PPh 3) 2 is produced when PdCl(OAr)(PPh 3) 2 decomposes. The reaction of PdCl 2(PPh 3) 2 with Bu 3Sn(OC 6H 4- p-OMe) also gave PdCl(Ph)(PPh 3) 2 in 8% isolated yield. These results suggest that PdCl(OAr)(PPh 3) 2 is highly labile and the aryloxy ligand exchanges with the phenyl groups in triphenylphosphine even under very mild conditions.