Preparation and C-Alkylation of Enantiomerically Pure<i>S</i>-Phenyl Aziridinecarbothioates. On the Structure of Small-Ring Ester Lithium Enolates
作者:Robert Häner、Bernardo Olano、Dieter Seebach
DOI:10.1002/hlca.19870700704
日期:1987.11.4
%, 18 examples; Schemes 1 and 4–6). The configurational stability of the lithiated species is studied, and conclusions about their structures are drawn. Thus, a C(α)-lithiated ester (see L, Scheme 9) or an O-lithiated ‘enolate’ (see M) with pyramidalized C(β)-atom is proposed for the species from levorotatory S-phenyl N-benzylaziridinecarbothioate which does not undergo racemization after 1 h at −60°
外消旋和对映体纯甲基N-(叔丁基) - ñ -苄基-和Ñ -1-(苯乙基)aziridinecarboxylates是通过已知方法制备并转化成硫酯苯基(1,2,15,16 ;方案2和3) 。在干冰温度下,将它们用二异丙基氨基锂(LDA)和BuLi(用于除去二异丙基胺)的THF质子化。所得的锂化物种非常稳定,可以氘化,烷基化(CH 3,C 2 H 5,烯丙基,苄基),并以良好的收率(50–80%,18个实例;方案1)添加到醛和硝基烯烃中。和4–6)。研究了锂化物种的构型稳定性,并得出了有关其结构的结论。因此,对于左旋S-苯基N-苄基氮丙啶碳硫酸盐的物种,提出了一种C(α)-锂化的酯(见L,方案9)或一个带有金字塔状C(β)原子的O-化的“烯醇盐”(见M)。在-60°(THF溶液)下1h后不发生外消旋作用。