Sigmatropic isomerizations in azaallyl systems: XXI. Alkanimidoylphosphonates and their prototropic and phosphorotropic isomers
作者:P. P. Onys’ko、T. V. Kim、E. I. Kiseleva、A. D. Sinitsa
DOI:10.1007/s11176-005-0110-8
日期:2004.12
Synthetic procedures for alkanimidoylphosphoryl derivatives with α-hydrogen atoms in the N-alkyl radical are developed. Data on the effect of substituents at the carbon and phosphorus atoms on the facility of prototropic transitions in the C=N-C triad are summarized. The most facile proton transfer occurs in the N-benzyl derivatives, and the prototropic isomer is the more stable, the stronger the electron-acceptor power of the substituent at the sp 3-carbon atom of the azaallyl triad. The proton transfer in N-(α-phenethyl)-trifluoroacetimidoylphosphonates proceeds selectively, which allows preparation of enantiomerically enriched derivatives of α-aminotrifluoroethylphosphonic acid. A specific effect of substituents at the phosphorus atom on the prototropism attendant on phosphorylation of imidoyl chlorides is demonstrated.