Syntheses and uses of azetidiniminium salts

Abstract

Tertiary amides are readily converted into iminium salts which react with imines in the presence of triethylamine to give azetidiniminium salts. Upon hydrolysis, thiolysis or aminolysis these are transformed into the corresponding β-lactams, azetidinethiones or azetidinimines. Chiral azetidi-niminium salts have been obtained in high optical purity from chiral iminium salts and imines. A new application of the Baeyer-Villiger oxidation has been found : it allows the conversion of azetidiniminium salts into oxazolidino-nes. Preliminary results on a new potential asymmetric synthesis of amino alcohols and amino acids are described. © 1987 IUPAC