Diastereoselectivity in asymmetric allylations: The role of vicinal chirality in the allyl nucleophile for S<sub>E</sub>2′ reactions with aldehydes
作者:David R Williams、Kevin G Meyer、Khalida Shamim、Samarjit Patnaik
DOI:10.1139/v03-168
日期:2004.2.1
A series of nonracemic homoallylic alcohols have been prepared by asymmetric allylation using the (R,R)- and (S,S)-1,2-diamino-1,2-diphenylethane bis-sulfonamide controller ligands for in situ formation of chiral B-allyl-1,3,2-diazaborolidines. Diastereofacial selectivity is influenced by adjacent stereochemistry incorporated into the allyl moiety at C-2, in addition to the expected role of the chiral
使用 (R,R)- 和 (S,S)-1,2-diamino-1,2-diphenylethane bis-sulfonamide 控制配体通过不对称烯丙基化制备了一系列非外消旋高烯丙醇,用于原位形成手性 B -烯丙基-1,3,2-二氮杂硼烷。除了手性助剂的预期作用外,非对映面选择性还受结合到 C-2 烯丙基部分的相邻立体化学的影响。醛反应物中的额外不对称性引入了三重立体分化。开发了一个模型来识别增强立体化学关系,并且示例已经确定了这些因素的相对重要性。该方法支持以高度收敛的方式构建复杂的高烯丙醇。 关键词:不对称烯丙基化,非对映选择性,1,4-立体控制,