directly introduce these acyl moieties by an enzyme-catalyzed reaction of 2a with the corresponding activated esters. This new approach was based on the regioselective introduction of a methyl malonate residue at the CH2OH of the sugar moiety by catalysis with the protease subtilisin ( 22a). The mixed diester 22a was then subjected to chemoselective hydrolysis of the methoxycarbonyl function by another