Benzyl glycolate may be used for the synthesis of the methyl [2-(2′-benzyloxy-2′-oxoethyl)-5-acetamido-4,7,8,9- tetra-O-acetyl-3,5-dideoxy-α- and -β-D-glycero-D-galacto-2-nonulopyranosid]onate. It may be used for the preparation of monosaccharide building blocks. It may also be used for the synthesis of the following new polymeric phosphazenes having pendent esters of glycolic or lactic acid as side units: · poly[bis(ethyl glycolato)phosphazene] · poly[bis(ethyl lactato)phosphazene] · poly[bis(benzyl glycolato)phosphazene] · poly[bis(benzyl lactato)phosphazene] Benzyl glycolate may be used for the synthesis of the methyl [2-(2′-benzyloxy-2′-oxoethyl)-5-acetamido-4,7,8,9- tetra-O-acetyl-3,5-dideoxy-α- and -β-D-glycero-D-galacto-2-nonulopyranosid]onate. It may be used for the preparation of monosaccharide building blocks. It may also be used for the synthesis of the following new polymeric phosphazenes having pendent esters of glycolic or lactic acid as side units: · poly[bis(ethyl glycolato)phosphazene] · poly[bis(ethyl lactato)phosphazene] · poly[bis(benzyl glycolato)phosphazene] · poly[bis(benzyl lactato)phosphazene]