Abstract |
The metal-mediated iminoacylation of ketoximes R1R2C= NOH (1a R-1 = R-2 = Me; 1b R-1 = Me, R-2 = Et; 1c R1R2 = C4H8; 1d R1R2 = C5H10) upon treatment with the platinum(II) complex trans-[PtCl2(NCCH2CO2Me)(2)] 2a with an organonitrile bearing an acceptor group proceeds under mild conditions in dry CH2Cl2 to give the trans-[PtCl2\NH= C(CH2CO2Me) ON= CR1R2\(2)] 3a - d isomers in moderate yield. The reaction of those ketoximes with trans-[PtCl2(NCCH2Cl)(2)] 2b under the same experimental conditions gives a 1 : 1 mixture of the isomers trans/cis-[PtCl2\NH= C(CH2Cl) ON= CR1R2\(2)] 3e - h and 4e - h in moderate to good yield. These reactions are greatly accelerated by microwave irradiation to give, with higher yields (ca. 75\%), the same products which were characterized by IR and H-1, C-13 and Pt-195 NMR spectroscopies, FAB-MS, elemental analysis for the stable trans isomers, and X-ray diffraction analysis (3f). The diiminoester ligand in 3a was liberated upon reaction of the complex with a diphosphine. |