Alkyl per-O-benzyl-β-d-glucopyranosides are rapidly anomerized into the corresponding α-anomer by TiCl4 in CH2Cl2 at 25°C. Replacement of the benzyl group at 0-6 by acetyl one dramatically slows the reaction but those of other benzyl groups at 0-2, 0-3, and 0-4 do not. A plausible scheme for the reaction in which benzyloxymethylene group and ring oxygen play an important role is presented.
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Morishima et al. (1979) studied this question.
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