SYNTHESIS OF GLYCOSYL AZIDES BY THE ADDITION OF PHENYLSELENENYL AZIDETO GLYCALS

The addition of phenylselenenyl azide to glycals is carried out under conditions that give 2-deoxy-2-phenylselenoglycosyl azides. This regio chemistry is opposite to that obtained under free-radical conditions, which are known to produce 2-azido-2-deoxyselenoglycosides. The additi on reaction is carried outwith phenylselenenyl chloride and sodium azi de in dimethylformamide, and is stereoselective for trans addition. Tr i-O-benzyl-D-glucal and di-O-benzyl-L-rhamnal each gave two addition p roducts, in which the phenylselenyl add azido groups were either trans diaxial or trans diequatorial. Tri-O-benzyl-D-galactal gave only the trans diaxial addition product.