Single-Step Symmetrical Double Alkylation of β,γ-Unsaturated δ-Lactams via Magnesium ‘Ate’ Complexes
作者:Jacek Sośnicki、Łukasz Struk
DOI:10.1055/s-0029-1217354
日期:2009.7
An easy approach to symmetrically 3,3-dialkylated derivatives of 3,6-dihydro-1H-pyridin-2-one in a one-pot and a single-step procedure via magnesium ‘ate’ complex is described. [Bu3Mg]Li used as the base showed great basic potential as one equivalent of it allowed double proton abstraction from 3,6-dihydro-1H-pyridin-2-one. Deprotonation at noncryogenic conditions yielded stable magnesiates which on treatment with more than two equivalents of alkyl halides provided 3,3-dialkylated products in good yield. In some cases minor 3,5-dialkylated lactams were formed due to allylic conjugation.
本文描述了一种通过镁“盐”复合物在单锅单步操作中合成对称的3,3-二烷基化的3,6-二氢-1H-吡啶-2-酮衍生物的简便方法。作为碱的[Bu3Mg]Li表现出了很大的碱性潜力,因为其一当量能够使3,6-二氢-1H-吡啶-2-酮发生双质子抽提。在非低温条件下去质子化生成了稳定的镁盐,在与超过两当量的烷基卤化物处理后,得到高产率的3,3-二烷基化产物。在某些情况下,由于烯丙 conjugation 形成了少量的3,5-二烷基化内酯。