2-Thiazolyl α-amino ketones: A new class of reactive intermediates for the stereocontrolled synthesis of unusual amino acids

Article abstract of DOI:10.1055/s-1993-26021

The thiazole-based one carbon homologation of four α-amino acids (L-phenylalanine, L-leucine, L-threonine, and L-serine) to the corresponding α-hydroxy β-amino aldehydes and acids in both configurations at C(α), is described. The methodology involves the following key operations: (i) the conversion of an α-amino ester to a 2-thiazolyl α-amino ketone; (ii) the stereocontrolled reduction of a ketone carbonyl to either syn or anti α,β-amino alcohols; (iii) the aldehyde release from the thiazole ring; (iv) the oxidation of the aldehyde to a carboxylic acid. The methodology was only partially applied to L-phenylglycine because of some limitations in operation (i).