containing chiral auxiliary have been employed to bring about 1,4-addition reactions to enones. These reactions generate δ-oxo-α-seleno esters in good yields and with excellent regio- and diastereoselectivities. The results obtained clearly indicate that the Lewis acids, employed to activate the starting enones towards addition, greatly influence reactivity as well as the stereochemical outcomes of
衍生自苯基
硒乙酸甲酯和其他带有手性助剂
硒的
乙酸盐的
钛烯醇化物已被用于对烯酮进行 1,4-加成反应。这些反应以良好的产率和出色的区域选择性和非对映选择性生成 δ-氧代-α-
硒代酯。获得的结果清楚地表明,用于激活起始烯酮加成的
路易斯酸极大地影响反应性以及这些反应的立体
化学结果。TiCl4 络合导致特别有效地促进 1,4-加成。有机
硒部分的简单操作允许一些对映体纯的 δ-氧-α-
樟脑硒酯转化为相应的 δ-氧-α-羟基或 δ-氧-α-烯丙基酯或三取代的
四氢呋喃。