Cyclization of Zincated α‐
<i>N</i>
‐Homoallylamino Nitriles: A New Entry to Enantiopure 2,3‐Methanopyrrolidines
作者:Sabrina Ouizem、Sandrine Cheramy、Candice Botuha、Fabrice Chemla、Franck Ferreira、Alejandro Pérez‐Luna
DOI:10.1002/chem.201001639
日期:2010.11.8
Stereoselective cyclization of zincated α‐N‐homoallylamino nitriles has been developed. Following treatment with lithium diisopropylamide (LDA) and transmetalation with zinc bromide, α‐N‐(1‐phenylethyl)‐N‐homoallylamino nitriles lead to 2,3‐methanopyrrolidines in moderate to good yields (up to 66 %) and excellent selectivities (up to >98:2). With substrates derived from α‐branched homoallylic amines
已开发出锌化的α- N-高烯丙基氨基腈的立体选择性环化反应。用二异丙基氨基锂(LDA)处理并用溴化锌,α - N-(1-苯乙基)-N-进行金属转移均烯丙基氨基腈以中等至良好的收率(高达66%)和极好的选择性(高达> 98:2)产生2,3-甲基吡咯烷酮。使用衍生自α-支化均胺的底物,观察到均聚物立构中心的立体定向反转。为了解决这个问题,提出了一种机械原理,涉及由锌化的α-氨基腈形成锌亚碘鎓离子。然后,应从涉及aza-Cope重排的序列中产生2,3-甲氧吡咯烷酮,从而提供构型稳定的(2-azoniaallyl)锌物种,然后进行[3 + 2]环加成反应。