Generation of Phosphoranes Derived from Phosphites. A New Class of Phosphorus Ylides Leading to High <i>E</i> Selectivity with Semi-stabilizing Groups in Wittig Olefinations
作者:Varinder K. Aggarwal、J. Robin Fulton、Chris G. Sheldon、Javier de Vicente
DOI:10.1021/ja029573x
日期:2003.5.1
Tosylhydrazones derived from aryl aldehydes react with t-BuOK, ClFeTPP, (MeO)3P, and aldehydes to furnish olefins with high E selectivity. These reactions occur through a Wittig-type pathway via the corresponding diazo compounds, metal carbenes and phosphorous ylides, with the water-soluble trimethyl phosphate as the byproduct. Similar reactions can also be performed using ethyl diazoacetate; however
源自芳基醛的甲苯磺酰腙与 t-BuOK、ClFeTPP、(MeO)3P 和醛反应以提供具有高 E 选择性的烯烃。这些反应通过相应的重氮化合物、金属卡宾和磷叶立德通过 Wittig 型途径发生,副产物为水溶性磷酸三甲酯。使用重氮乙酸乙酯也可以进行类似的反应;然而,仅在 LiBr 存在下才观察到高 E 选择性。在这种情况下,该反应被认为是通过通过 Arbuzov 反应形成的膦酸阴离子发生的。因此,该烯化反应通过 Horner-Wadsworth-Emmons (HWE) 反应发生,但膦酸阴离子是在完全无碱的条件下生成的。