Deslongchamps P, Li S, Dory YL. Hydrolysis of alpha- and beta-glycosides. New experimental data and modeling of reaction pathways.
Org Lett 2004;
6:505-8. [PMID:
14961609 DOI:
10.1021/ol036220+]
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Abstract
[reaction: see text] The cyclization of oxocarbenium ion conformers 6alpha and 6beta (from 11E and 11Z) gave only the beta-glycoside 1beta, and the addition of methanol to the oxocarbenium ion 3 yielded mainly the alpha-glycoside 1alpha with both experiments being carried out under kinetically controlled conditions. RHF/6.31G calculations reproduce well these experimental results and show that the endocyclic and the exocyclic C-O bond cleavage processes can compete in the hydrolysis of 1beta, whereas 1alpha gets hydrolyzed by exocyclic C-O bond cleavage only.
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