The Aza-[2,3]-Wittig Sigmatropic Rearrangement of Acyclic Amines: Scope and Limitations of Silicon Assistance
作者:James C. Anderson、Alice Flaherty、Martin E. Swarbrick
DOI:10.1021/jo0056343
日期:2000.12.1
trialkylsilyl substituent into allylic amine precursors allows the base-induced aza-[2,3]-Wittig sigmatropic rearrangement to proceed in excellent yield and diastereoselectivity. The rearrangement precursors require a carbonyl-based nitrogen protecting group that must be stable to the excess of strong base required for the reaction. The N-Boc and N-benzoyl group are very good at stabilizing the product
在烯丙基胺前体中包含C-2三烷基甲硅烷基取代基可以使碱诱导的aza- [2,3] -Wittigσ重排以优异的收率和非对映选择性进行。重排前体需要基于羰基的氮保护基团,该基团必须对反应所需的过量强碱稳定。N-Boc和N-苯甲酰基在稳定产物阴离子和引发去质子方面非常出色。迁移基团(G)需要通过共振来稳定初始阴离子,并且需要G-CH(3)()pK(a)> 22,以便初始阴离子具有足够的反应性以进行重排。产物7、20b-d,f,g和23以高(10-20:1)抗非对映选择性形成。含有吗啉酰胺基的产物23可用于制备其他羰基衍生物。