N-acylimidazolidin-2-ones: new chiral auxiliaries for carboxylic acid alkylation
摘要:
Chiral N-acylated imidazolidin-2-ones, readily available from aminoethanols in three steps through the nucleophilic opening of oxazoline intermediates, have been demonstrated to undergo highly diastereoselective benzylations and methylations via their sodium enolates. In most cases, the resulting products are highly crystalline, and the chiral auxiliaries can be readily recycled. (C) 1997 Elsevier Science Ltd.
Stereoselective Synthesis of Quaternary Center Bearing Azetines and Their β-Amino Acid Derivatives
作者:Christopher J. MacNevin、Rhonda L. Moore、Dennis C. Liotta
DOI:10.1021/jo7018202
日期:2008.2.1
We describe here the use of a stable, four-membered azetine heterocycle for the preparation of highly substituted β-amino acid derivatives. Imidazolidinone chiral auxiliaries were found to eliminate a competitive reaction pathway that had been present under previously reported conditions for azetine synthesis. The ephedrine derived imidazolidin-2-one 21 was allowed to react as its chlorotitanium enolate