STEREOSELECTIVE SYNTHESIS OF THE CORE STRUCTURE OF THE NEPHRITOGENOSIDE GLYCOPEPTIDE

A new strategy for the construction of the O-glycoside bond in the nep hritogenoside unit using the phenylsulfenyl method is reported. The re adily accessible phenylsulfinyl glycoside proved to be an excellent gl ycosyl donor, leading to high yields and good selectivity. The extreme ly mild conditions utilized in glycosylation reactions allow trityl an d other sensitive protecting groups to be used for temporary protectio n. The fact that phenyl thioglycosides function as glycosyl acceptors during the coupling reaction and can easily be transformed into glycos yl donors by conversion to phenylsulfinyl glycosides, enables complex oligosaccharides to be prepared in a highly convenient manner.