The synthesis of amino acids by 1,3-dipolar cycloadditions of azomethine ylides

Abstract

Thiazolium ylides react with a variety of dipolarophiles to afford adducts. After filtration chromatography, a tricyclic adduct is obtained. The tricyclic adducts react with potassium t-butoxide/t-butanol to provide dihydropyrroles. The adducts also react with tributyltin hydride to form compounds in which the thiazolidine ring has been cleaved. These adducts can be hydrolyzed under acidic conditions to form pyrrolidines. The desulfurization procedure is significant in that none of the relative asymmetry derived from the dipolar cycloaddition is lost. The synthesis of α-allokainic acid has been achieved from adduct 16s.