Asymmetric\ Synthesis of Chiral Cyclic Amino Acids by Diels-Alder Reactions of (2S)- and (2R)-4-Methyleneoxazolidin-5-ones

Abstract

The synthesis of chiral (2S)- and (2R)-4-methyleneoxazolidin-5-ones, in high enantiomeric purity from (S)-S- methylcysteine, and their highly exo-selective Diels -Alder reactions with cyclic dienes are described. (1R,2S,4S)-2-Aminobicyclo[2.2.1]heptane-2-carboxylic acid has been prepared in 92% e.e. by these methods. A number of the products have been characterized by single-crystal X-ray methods, and their structure systematics examined.