Nk. Kochetkov et al., GLYCOSYLATION BY SUGAR 1,2-O-(1-CYANOBENZYLIDENE) DERIVATIVES - INFLUENCE OF GLYCOSYL-DONOR STRUCTURE AND PROMOTER, Carbohydrate research, 244(1), 1993, pp. 85-97
,2-O-(1-cyanobenzylidene)-alpha-D-galactopyranoses with differently su
bstituted aromatic nuclei have been synthesised and used as glycosyl d
onors in reactions with the acceptors methyl 4-tri-O-acetyl-6-O-trityl
-beta-D-galactopyranoside (11) and methyl 6-tri-O-acetyl-3-O-trityl-be
ta-D-galactopyranoside (12). The glycosylation of 11 gave only beta pr
oducts. The efficiency and stereoselectivity of the glycosylations of
12 depend on the nature of the substituent in the aromatic ring. The s
tereoselectivity for the formation of 1,2-trans-glycosidic bonds was t
he highest with the p-methoxy-benzylidene derivative with triphenylmet
hylium triflate as the promoter.