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.
开发了含有α-氢原子的N-烷基自由基的烷基脲膦酰基衍生物的合成方法。总结了碳原子和磷原子上的取代基对C=N-C三元组中质子转移便利性的影响数据。在N-苄基衍生物中,质子转移最为容易,随着位于氮杂烯三元组的sp³碳原子上的取代基的电子受体能力增强,质子异构体愈加稳定。在N-(α-苯乙基)-三氟乙酰基脲膦酸酯中,质子转移选择性进行,这使得能够制备富含对映体的α-氨基三氟乙基膦酸的衍生物。证实了磷原子上取代基对氯脲酰化反应中伴随的质子转移的特定影响。