A Useful Synthetic Method of dl-Threonine Using α-Isocyanoacetamides

Abstract

A reaction of α-isocyanoacetic acid amides (Ib-g) with acetaldehyde was carried out to develop a useful method for the synthesis of threonine. The reaction in the presence of potassium hydroxide in methanol afforded predominantly trans-5-methyl-4-N‣-substituted-aminocarbonyl-2-oxazoline (IIIb-f), which was easily hydrolyzed to dl-threonine, in a high yield. This method was extended to the synthesis of threo-β-hydroxy nor valine and threo-β-hydroxyleucine in excellent yields.