Stereoselectivity of the Radical Reductive Alkylation of Enamines: Importance of the Allylic 1,3-Strain Model
作者:Serge Schubert、Philippe Renaud、Pierre-Alain Carrupt、Kurt Schenk
DOI:10.1002/hlca.19930760707
日期:1993.11.3
of the cis-disubstituted cycloalkanes. In acyclic systems such as enamines derived from propiophenone and diethyl ketone, moderate to high stereoselectivities were observed in the H-abstraction step. A model based principally on minimization of allylic 1,3-strain (A1,3 strain) was deduced from the experimental results and semi-empirical (AM1) calculations.
据报道使用Bu 3 SnH作为还原剂向烯胺中自由基加成(方案2和4)。在不同系统中检查了这些反应的非对映选择性(表1和2)。衍生自环状酮(例如环己酮)的烯胺以高非对映选择性被烷基化,并优先形成顺式-二取代的环烷烃。在无环体系中,例如衍生自苯丙酮和二乙基酮的烯胺,在H提取步骤中观察到中等到高的立体选择性。主要基于最小化烯丙基1,3-应变(A 1,3 应变)是根据实验结果和半经验(AM1)计算得出的。