A facile and stereocontrolled synthesis of syn-α-alkyl α-hydroxy β-amino acids
摘要:
The diastereoselective synthesis of syn-alpha-alkyl alpha-hydroxy beta-amino acids 4a-h was easily accomplished by reaction of the sodium dianion of the corresponding anti alpha-alkyl beta-benzoylamino acid methyl eaters with iodine. The intermediate alpha-iodo derivatives spontaneously afforded cis-oxazolines which, upon hydrolysis, provided the desired products, with diastereoselectivities up to 99:1. (C) 1999 Elsevier Science Ltd. All rights reserved.
A new method for the preparation of 2,2,3-trisubstituted methyl 1-benzoylaziridine-2-carboxylates is reported. These compounds have been obtained starting from α-alkyl β-amino acids by formation of the lithium dianion and reaction with iodine. The aziridines undergo ring expansion or ring opening, depending on the substituents of the aziridine ring and on the reaction conditions. Following these methods