A new method of synthesis of racemic β-amino acids 6 by reduction of masked N-substituted and N-unsubstituted β-enamino acid derivatives 4via C-protected β-amino acids5 is described. The process occurs with high yields, total chemoselectivity and moderate diastereoselectivity. Readily available starting materials, inexpensive reagents and mild conditions are used to furnish derivatives 5 and 6.
A new, mild two-step synthesis of racemic p-amino acids starting from 2-allkyl-Delta (2)-oxazolines is described. The process implies the initial formation of masked N-substituted or N-unsubstituted beta -enamino acid derivatives followed by chemoselective reduction of the enamino moiety. The process takes place with high yields, total chemoselectivity and moderate diastereoselectivity. (C) 2001 Elsevier Science Ltd. All rights reserved.
An Efficient and Simple Entry to <i>N</i>-Substituted β-Enamino Acid Derivatives from 2-Alkyl-2-oxazolines and 2-Alkyl-2-thiazolines
作者:Santos Fustero、Antonio Navarro、Dolores Díaz、Marta G. de la Torre、Amparo Asensio、Francisco Sanz、M. Liu González
DOI:10.1021/jo961037y
日期:1996.1.1
provide the correct geometry of these derivatives. Structural considerations among the possible isomers of compounds 1 are discussed. From these studies it was concluded that the theoretical calculations agree with the experimental results. In addition, a very simple one-pot procedure for the preparation of masked N-substituted alpha-alkylated beta-enamino acidderivatives 2 from 6, 7, and different alkyl