Copper-Free Asymmetric Allylic Alkylation with Grignard Reagents
作者:Olivier Jackowski、Alexandre Alexakis
DOI:10.1002/anie.201000577
日期:2010.4.26
Open wide and say AAA: The copper‐free asymmetric allylicalkylation reaction of Grignardreagents, catalyzed by N‐heterocyclic carbenes, is reported for allyl bromide derivatives. This reaction offers good enantioselectivity and good to excellent γ regioselectivity, particularly for the formation of quaternary chiral centers (see scheme; Mes=mesityl).
张开嘴说AAA:据报道,N-杂环卡宾催化了格氏试剂的无铜不对称烯丙基烷基化反应,是烯丙基溴衍生物的反应。该反应提供了良好的对映选择性和良好的至优异的γ区域选择性,特别是对于形成四元手性中心(参见方案; Mes =甲磺酰基)。
A novel one-pot method for the stereoselective synthesis of tetrahydropyrimidinones in a low melting mixture
A direct and metal free one-pot method has been developed for the stereoselectivesynthesis of tetrahydropyrimidinone derivatives from a vinyl arene and formaldehyde using a tartaric acid–dimethylurea (TA : DMU) melt as a green reaction medium. The substrate scope of this method is very general and the tetrahydropyrimidinone (THPM) derivatives are synthesized in good yields with a high degree of diastereoselectivity
Magnesium hydride, generated in situ by solvothermal treatment of sodium hydride and magnesium iodide in tetrahydrofuran, was found capable of inducing regio and stereocontrolled hydromagnesiation of 2-aryl-1,3-dienes to form allylmagnesium species. Downstream functionalization of the resulting allylmagnesium species with various electrophiles provided synthetically valuable synthons such as homoallylic