Substituent effects in endocyclic cleavage–recyclization anomerization reaction of pyranosides

Pyranosides with 2,3-trans carbamate or 2,3-trans carbonate groups are anomerized under mild acidic conditions via endocyclic cleavage reaction. In order to understand the nature of the anomerization reaction via the endocyclic cleavage–recyclization process, the substituent effects at various positions were investigated.