Titanium-Mediated Diastereoselective Formation of (E)- or (Z)-2-Substituted 1-Vinylcyclopropanols: Scope and Limitation, Applications
作者:Sandrine Racouchot、Isabelle Sylvestre、Jean Ollivier、Yuri Yu. Kozyrkov、Alexei Pukin、Oleg G. Kulinkovich、Jacques Salaün
DOI:10.1002/1099-0690(200207)2002:13<2160::aid-ejoc2160>3.0.co;2-1
日期:2002.7
with the allylic double bond being created subsequently (Knoevenagel condensation or dehydrohalogenation). Titanium-mediated cyclopropanation of homoallyl alk-2-enoates, on the other hand, directly provided the corresponding Z diastereomers. Palladium(0)-catalysed azidation of their sulfonic esters (tosylate, mesylate), azide reduction, and subsequent double bond cleavage afforded (E)- or (Z)-2-alkyl-2
钛介导的 α,β-不饱和酯的环丙烷化未能以有用的产率提供 1-乙烯基环丙醇衍生物,但 (E)-2-取代-1-乙烯基环丙醇是由 O-保护的 β-氧代-和 β-卤代酯非对映选择性地形成的,随后产生烯丙基双键(Knoevenagel 缩合或脱卤化氢)。另一方面,钛介导的高烯丙基烷-2-烯酸酯的环丙烷化直接提供了相应的 Z 非对映异构体。钯 (0) 催化其磺酸酯(甲苯磺酸酯、甲磺酸酯)的叠氮化、叠氮化物还原和随后的双键裂解得到 (E)- 或 (Z)-2-烷基-2,3- 甲氨基氨基酸,尽管需要改进通过这些方法进行三元环分子的完全不对称合成。(© Wiley-VCH Verlag GmbH, 69451 Weinheim,