Ia. Ivanova et Av. Nikolaev, SYNTHESIS OF BETA-D-TALOPYRANOSIDES AND BETA-D-MANNOPYRANOSIDES VIA INTRAMOLECULAR NUCLEOPHILIC-SUBSTITUTION, Journal of the Chemical Society. Perkin transactions. I (Print), (18), 1998, pp. 3093-3099
The selective and efficient syntheses of beta-D-talopyranosides and be
ta-D-mannopyranosides were achieved from beta-D-galactopyranosides and
beta-D-glucopyranosides, respectively, that carry a benzoyl group at
O-3 and a triflyl group at O-2. The transformation was performed in th
e presence of an alcohol via intramolecular nucleophilic attack of the
benzoyl group with inversion of configuration at C-2 that provided, f
irst, the formation of the corresponding 2,3-(alkyl orthobenzoates) of
the desired beta-D-talopyranosides or beta-D-mannopyranosides, follow
ed by acidic opening of the cyclic orthoesters.