energy refinements. The resulting proposed model for the origins of stereocontrol in this reaction has been tested by experiment. The reactions lead to a high cis diastereoselectivity across the THP ring due to the preference for both the alkoxide and the 6-substituent to sit equatorial in the alkylation transition structure. In the oxy-Michael addition of these lactolates to beta-substituted nitroolefins
通过从头算(MP2)能量优化的密度泛函(B3LYP)计算,研究了“裸” 6-取代的δ-
乳酸酯的烷基化和迈克尔加成中的非对映选择性。已经通过实验测试了所提出的用于该反应中立体控制起源的模型。由于偏爱醇盐和6-取代基都位于烷基化过渡结构中的赤道,该反应导致整个THP环具有很高的顺式非对映选择性。在将这些
乳酸酯的氧基-迈克尔加成到β-取代的硝基烯烃中时,我们提出对硝基的高非对映选择性β-是空间,立体电子和溶剂化因子结合的结果。