REGIOSPECIFIC 4,6-FUNCTIONALIZATION OF PYRANOSIDES VIA DIMETHYLBORON - BROMIDE-MEDIATED CLEAVAGE OF PHTHALIDE ORTHOESTERS

An efficient strategy for regiocontrolled differentiation of the 4,6-p ositions of pyranosides has been developed using dimethylboron bromide -mediated cleavage of phthalide orthoesters. The reaction proceeds und er mild conditions, is tolerant of additional acetal functionality, an d produces a benzoate bearing suitable functionality for intramolecula r assisted cleavage in the presence of SAc, OAc, and NHAc groups.