Amidines Derived from Pt(IV)-Mediated Nitrile−Amino Alcohol Coupling and Their Zn(II)-Catalyzed Conversion into Oxazolines

The reaction between the platinum(IV) complex trans-[PtCl4(EtCN)2] and the amino alcohols NH2CH2CH2OH, NH2CH2CH(Me)OH-(R)-(−), NH2CH(Ph)CH2OH-(R)-(−), NH2CH(Et)CH2OH-(R)-(−), NH2CH(Et)CH2OH-(S)-(+), and NH2CH(Prn)CH2OH proceeds rapidly at room temperature in CH2Cl2 to furnish the amidine complexes [PtCl4{HNC(Et)NH⌒OH}2] (1−6) in good yield (70−80%). The related reaction between the platinum(II) complex trans-[PtCl2(EtCN)2] and monoethanolamine in a molar ratio of 1:2 in CH2Cl2 results in the addition of 4 equiv of NH2CH2CH2OH per mole of complex to give [Pt{HNC(Et)NHCH2CH2OH}2(NH2CH2CH2OH)2]2+ (7). Formulation of 1−6 is based upon satisfactory C, H, N elemental analyses, electrospray mass spectrometry, IR spectroscopy, and 1H, 13C{1H}, 15N, and 195Pt NMR spectroscopies, while the structures of trans-[PtCl4{(Z)-NHC(Et)NHCH2CH2OH}2] (1), trans-[PtCl4{(Z)-NHC(Et)NHCH2CH(Me)OH-(R)-(−)}2] (2), and trans-[PtCl4{(Z)-NHC(Et)NHCH(Et)CH2OH-(R)-(−)}2] (4) were determined by X-ray single-crystal diffraction. The Z-am...