Insertion Reactions of Isocyanides into the Metal-C(sp3) Bonds of Ylide Complexes

Abstract

The synthesis of the previously reported complexes [Pd(C,C-CHCO2R)2PPh2}(mu-Cl)]2 (R = Me (1), Et (2)) has been considerably improved by reacting the phosphonium salts [Ph2P(CH2CO2R)2]Cl with Pd(OAc)2. Complexes 1 and 2 react with isocyanides R'NC (R' = C6H4Me2-2,6 (Xy), C6H4I-2 and tBu) to give complexes of the type [Pd{C,C-{C(CO2R)=C(NHR')}(CHCO2R)PPh2}Cl(CNR')], resulting from the insertion of the unsaturated molecule in one of their Pd-C bonds and the hydrogen transfer from the methine CH to the iminobenzoyl nitrogen. These are the first insertion reactions observed in the Pd-C bond of a P-ylide complex. The crystal structure of the complex [Pd{C,C-{C(CO2Me)=C(NHXy)}(CHCO2Me)PPh2}Cl(CNXy)] (3) is reported.