Stereoselective Synthesis of Highly Functionalized Cyclopropanes. Application to the Asymmetric Synthesis of (1<i>S</i>,2<i>S</i>)-2,3-Methanoamino Acids
作者:Philippe Dorizon、Guifa Su、Gitte Ludvig、Lilyia Nikitina、Renée Paugam、Jean Ollivier、Jacques Salaün
DOI:10.1021/jo982528g
日期:1999.6.1
functionalized cyclopropanes (E)-4a-d, diastereoselectivity, (de 88-100%). Several attempts to achieve the asymmetric synthesis of the 1-amino-2-ethenylcyclopropanecarbonitrile (E)-9, by means of this new procedure, i.e., using chiral palladium ligands, chiral aminoacetonitriles (-)- and (+)-12 (from 1-hydroxypinanone) or chiral allyl chlorides (4S)-20b-d and (4R)-20e (from (2S) ethyl lactate) have pointed up
一锅钯(0)催化的α-取代的腈2a-d的阴离子对1,4-二氯丁-2-烯1进行烷基化和S(N)(')环化可提供高度官能化的环丙烷(E)- 4a-d,非对映选择性,(de 88-100%)。通过这种新方法,进行了一些尝试来实现1-氨基-2-乙烯基环丙烷甲腈(E)-9的不对称合成,即使用手性钯配体,手性氨基乙腈(-)-和(+)-12(来自1-羟基吡啶酮)或手性烯丙基氯(4S)-20b-d和(4R)-20e(来自(2S)乳酸乙酯)指出了钯催化环化步骤的可逆性,这导致观察到的低对映选择性(ee 88%),并提供对映体富集的1-氨基-2-丙烯基环丙烷甲腈(E)-22(ee> 83%)的(1S,2S)-2,3-甲基氨基酸的合适前体。