Synthesis and destannylation of η3-1-stannylallylpalladium(II) complexes

Reaction of 1-tributylstannyl-3-chloropropene with a Pd(PPh3) species, generated in situ from Pd2(dba)3 and two equivalents of PPh3, afforded Pd(η3-Bu3SnCHCHCH2)Cl(PPh3) (1). Complex 1 underwent PPh3 promoted protodestannylation with acetic acid or diethyl malonate to give an unsubstituted η3-allylpalladium moiety as either a detectable product or a reaction intermediate. The reaction of 1 with PPh3 and 0.5 equivalent of PdCl2(PhCN)2 afforded the dinuclear complex (μ-1-3-η3:4-6-η3-CH2CHCHCHCHCH2){PdCl(PPh3)}2 (4) containing a hexatriene ligand, a formal vinylcarbene dimer.