A STUDY ON THE Z-SELECTIVE HORNER-WADSWORTH-EMMONS (HWE) REACTION OF METHYL DIARYLPHOSPHONOACETATES
作者:Keisuke Kokin、Ken-Ichro Iitake、Yutaka Takaguchi、Hiromu Aoyama、Sadao Hayashi、Jiro Motoyoshiya
DOI:10.1080/10426509808032451
日期:1998.1
aromatic and aliphatic aldehydes. While the phosphonoacetate (3) with bis(2,4-difluorophenyl)phosphono group showed the highest Z-selectivity in all reaction conditions employed, decrease of the selectivity was observed in the case of some phosphonoacetates with diarylphosphono groups. These experimental results and the theoretical studies calculated by AM1 or 3-21G* ab initio methods suggested that
摘要 进行了实验和理论研究,以探索采用几种二芳基膦酰乙酸甲酯(3、4、5 和 6)和醛的 Homer-Wadsworth-Emmons (HWE) 反应中的 Z 选择性。Z-选择性取决于反应条件,例如碱、反应温度和磷原子上的芳香族取代基,但本研究中使用的几乎膦酰基乙酸酯在与芳香族和脂肪族醛的反应中都表现出 Z-选择性。虽然具有双(2,4-二氟苯基)膦酰基的膦酰基乙酸酯(3)在所采用的所有反应条件中显示出最高的Z-选择性,但在某些具有二芳基膦酰基的膦酰基乙酸酯的情况下观察到选择性降低。这些实验结果和通过 AM1 或 3-21G* ab initio 方法计算的理论研究表明,加成步骤过渡态中的空间效应比电子效应更重要。重新...的不同方面