A new class of amine N-oxides derived from trans-2,5-diphenylpyrrolidine were synthesized in enantiomerically pure form and tested as metal-free catalysts in the reaction of aldehydes with allyl(trichloro)silane to afford homoallylic alcohols. The products were obtained in fair to good yields and up to 85% ee. The behavior of structurally different catalysts and the influence of a coordinating unit present in the organocatalyst on controlling the stereochemical efficiency of the reaction were also investigated. Noteworthy a catalyst capable of promoting the allylation of aliphatic aldehydes with an almost unprecedent and unusually high enantioselectivity, up to 85%, was identified.
一种新型胺N-氧化物类化合物,源自反式-2,5-二苯基
吡咯烷,以纯手性形式合成,并测试作为无
金属催化剂,在醛与烯丙基(三
氯)
硅烷反应中,得到同
烯丙醇。产物收率尚可至良好,最高可达85% 的对映体过量。研究了结构不同的催化剂行为,以及有机催化剂中存在的配位单元对反应立体
化学效率的影响。值得注意的是,发现了一种催化剂,能以几乎前所未有的高度对映选择性(高达85%)促进脂肪醛的烯丙基化反应。