Samariumdiiodide is an efficient catalyst for the aza-Michael addition of O-benzylhydroxylamine to α,β-unsaturated N-acyloxazolidinones leading to mixtures of the Michael adduct and the product resulting from its amidation. Samarium iodobinaphtholate catalyzed reactions selectively afford the Michael adducts with enantiomeric excesses up to 88 %. An isoinversion effect with temperature is observed
二碘化钐是一种有效的催化剂,用于将 O-苄基羟胺与 α,β-不饱和 N-酰基恶唑烷酮进行氮杂-迈克尔加成,从而形成迈克尔加合物及其酰胺化产物的混合物。碘联萘酸钐催化的反应选择性地提供对映体过量高达 88% 的迈克尔加合物。在 -40 °C 时观察到对映体过量最高的温度的同位倒置效应。
Insight into the structure of the precatalyst and active species for samarium iodo binaphtholate catalysed aminolysis of epoxides
Samarium iodo binaphtholate is an efficient Lewis acid catalyst for the enantioselective carbon-nitrogen bond formation such as aza-Michael reactions and the aminolysis of epoxides allowing highly enantioenriched aminoalcohols and aminoacids building blocks to be prepared. Various studies including the relationship between enantiomeric excess and temperature and observation of non linear effects for these reactions indicate the importance of the amine for the formation of the catalytic species. Results support the proposal of dimeric or more aggregated structures for samarium iodo binaphtholate and of a bimetallic active species for the aminolysis of epoxides. (C) 2010 Elsevier Ltd. All rights reserved.
Enantioselective aza-Michael reactions catalyzed by samarium iodobinaphtholate
作者:Iréna Reboule、Richard Gil、Jacqueline Collin
DOI:10.1016/j.tetasy.2005.10.022
日期:2005.11
Samarium iodobinaphtholate is an efficient enantioselective catalyst for the Michael addition of aromatic amines to fumaryl oxazolidinone affording aspartic acid derivatives in good yields. Influence of temperature on the addition of p-anisidine revealed an isoinversion effect with the maximum enantiomeric excess of 88% at -40 degrees C. (c) 2005 Elsevier Ltd. All rights reserved.