L-Selectride-Mediated Highly Diastereoselective Asymmetric Reductive Aldol Reaction: Access to an Important Subunit for Bioactive Molecules
作者:Arun K. Ghosh、Jorden Kass、David D. Anderson、Xiaoming Xu、Christine Marian
DOI:10.1021/ol801971t
日期:2008.11.6
L-selectride reduction of a chiral or achiral enone followed by reaction of the resulting enolate with optically active alpha-alkoxy aldehydes proceeded with excellent diastereoselectivity. The resulting alpha,alpha-dimethyl-beta-hydroxy ketones are inherent to a variety of biologically active natural products.
An approach to beta-lactams via a Kinugasa reaction between chiral copper acetylides and chiral acyclic nitrones bearing either 1,3-dioxane or 1,3-dioxolane moieties is reported. The stereochemical preferences observed in these reactions are discussed. The reaction provides access to a variety of interesting beta-lactam structures. Electronic circular dichroism in combination with NMR spectroscopy was shown to be a useful and effective method for the reliable determination of the absolute configuration of all components of a complex mixtures of azetidinones. The effectiveness of the chiral analysis of complex mixtures was demonstrated for HPLC coupled on-line with electronic circular dichroism detection as well. (C) 2015 Elsevier Ltd. All rights reserved.