An expeditious route to GlcNAc-Cbz-Asn by chemo-enzymatic synthesis

A short-step route to GlcNAc-Cbz-Asn was developed. Treatment of GIcNAc in sat. aq. NH 4 HCO 3 solution and subsequent electorodialytic desalting provided ammonia-free glycosylamine in large quantity. The product was coupled with Cbz-Asn α-isobutyl ester β-fluoride, and finally, the isobutyl ester was deprotected by enzyme-catalyzed hydrolysis under mild conditions.