ABSTRACT
A very efficient three-component synthesis of a series of syn α-hydroxy-ß-amino esters, obtained in high diastereoselection and yield, was realized starting from an aldehyde, benzylamine, and the ketene silyl acetals derived from Ley's lactones. The synthetic protocol was optimized and the above compounds were obtained without the isolation of intermediates. The origin of the observed diastereoselection was investigated through a computational model of the key reaction step.
Subject(s)
Amino Acids/chemistry , Amino Acids/chemical synthesis , Lewis Acids/chemistry , Aldehydes/chemistry , Amines/chemistry , Catalysis , Ethylenes/chemistry , Ketones/chemistry , Models, Molecular , Molecular Conformation , Stereoisomerism , Substrate SpecificityABSTRACT
The 'one-pot' stereoselective conversion of N-(4-nitrobenzene)sulfonyl-alpha-amino acid tert-butyl esters into the corresponding N-alkyl-alpha-(4-nitrophenyl)-alpha-amino esters has been realized through N-alkylation of the starting amido esters, followed by N-C(alpha) migration of the p-nitrophenyl group and the loss of sulfur dioxide; the asymmetric induction is determined by an intermediate non-racemic enolate, without the need of an external source of chirality.