Enantiomerically pure substituted oxaaza compounds, salts of the same, and processes for the preparation of both

摘要

This invention provides a method for conveniently obtaining a compound of formula (Ia) which is a production intermediate of antimicrobial compounds, in which a salt of optically active acid of formula (IIIa) is obtained by allowing a compound of formula (I), a ketone compound and an optically active acid to react with one another, converted into its free form and then hydrolyzed.In the formula, R1: hydrogen atom or alkyl, aryl or aralkyl group; R2: hydrogen atom or alkyl, aryl, aralkyl, acyl, alkyloxycarbonyl, aralkyloxycarbonyl or substituted sulfonyl; these may further have substituents.)