Tandem Cycloaddition Chemistry of Nitroalkenes: Preparative and Theoretical Studies on the Stereochemical Course of [3 + 2] Cycloaddition of Cyclic Nitronates
作者:Scott E. Denmark、Mark Seierstad、B. Herbert
DOI:10.1021/jo9818374
日期:1999.2.1
Intermolecular [3 + 2] cycloadditions between two cyclic nitronates and a series of dipolarophiles are examined. High facial selectivity is observed in all cases and is analyzed with the aid of ab initio transition structure calculations. Monosubstituted dipolarophiles reacted with exclusive regiocontrol. Disubstituted dipolarophiles reacted with varying degrees of regiocontrol, which was dependent
研究了两个环状硝酸酯与一系列偶极亲和剂之间的分子间[3 + 2]环加成反应。在所有情况下均观察到较高的面部选择性,并通过从头算过渡结构计算进行分析。单取代的双极性亲和剂与独家区域控制反应。双取代的亲油性与不同程度的区域控制反应,这取决于取代基。讨论了预测区域选择性的理论方法。由于空间效应,通常优选Exo选择性,并且对于顺式-二取代的双亲性试剂尤其如此。