T. Ziegler et al., Prearranged glycosides. Part 14: Intramolecular glycosylation of non-symmetrically tethered glycosides, TETRAHEDR L, 42(4), 2001, pp. 569-572
Partially benzylated 1-thio-beta -D-glucopyranosides were tethered via posi
tion 2 to position 3 of methyl alpha -D-glucopyranosyl and benzyl 2-phthali
mido-2-deoxy-beta -D-glucopyranosyl derivatives, respectively, by non-symme
trical o-, m-, and p-methylbenzoate linkers. Intramolecular glycosylation o
f these prearranged glycosides lead to the corresponding non-symmetrically
tethered alpha-(1-->4)-linked disaccharides as the exclusive or main produc
ts. The tethers were regioselectively opened by transesterification affordi
ng isomeric disaccharide accepters which are susceptible for further elonga
tion of the sugar chain at positions 3 and 2', respectively. (C) 2001 Elsev
ier Science Ltd. All rights reserved.