Comparing of endocyclic and exocyclic cleavage reactions using mycothiol synthesis as an example

Glycosides can be cleaved in either an exo- or endocyclic fashion. Specifically, the former pathway is used during conventional glycosylation; whereas the latter pathway has not been the subject of attention. Endocyclic cleavage reaction enable the anomerization of β-glycosides to α-glycosides. Herein, we compared the efficacies of endo- and exocyclic cleavage reactions during the synthesis of mycothiol, a potential drug development target for tuberculosis treatment, in terms of selectivity and product yield. In addition, the direct resolution of benzyl-protected inositol by a highly stereoselective glycosylation reaction was investigated.