Insight into the structure of the precatalyst and active species for samarium iodo binaphtholate catalysed aminolysis of epoxides
摘要:
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.
Synthesis of Rare Earth Catalysts and Their Applications for Enantioselective Synthesis of Heterocyclic β-Amino Alcohols
作者:Myriam Martin、Ahmad El Hellani、Jing Yang、Jacqueline Collin、Sophie Bezzenine-Lafollée
DOI:10.1021/jo2019015
日期:2011.12.2
A new family of chiral lanthanide complexes derived from (R)-binaphthol has been synthesized by a one-pot procedure using only commercially available substrates. These complexes were evaluated for the aminolysis of mesoepoxides and proved to be efficient enantioselective catalysts. The samarium complex coordinated by two (R)-binaphthoxide ligands was the most enantioselective catalyst of this series. beta-Amino alcohols including heterocycles have been isolated with enantiomeric excesses up to 84%.