Gold(I) complexes containing the cationic ylide ligand bis(methyldiphenylphosphonio)methylide

The ylide Ph2PCH=PPh2Me can be selectively P-alkylated by Mel or MeO3SCF3 t o form the bis(methyldiphenylphosphonio)methylide salts [MePPh2CHPPh2Me]A ( A=I (1), CF3SO3 (2)). The ylidic carbon shows a weak nucleophilicity and do es not give typical reactions with common organic electrophiles, including Wittig type reactions, but it is able to displace tetrahydrothiophene in [A uX(tht)] to give the corresponding C-coordinated gold(I) compounds [Au{CH(P Ph2Me)(2)}X]CF3SO3 (X=Cl (3), C6F5 (4)). The crystal structure of (4) displ ays a linear coordination for the gold atom, single P-C bond lengths and a PCP angle of 119.1(3)degrees for the ligand. (C) 2000 Elsevier Science Ltd. All rights reserved.