On the basis for regioselective oxidation within a tetragalloylpyranose substrate

Article abstract of DOI:10.1016/S0040-4039(98)01986-8

Lead (IV)-mediated oxidation of a benzyl 2,3,4,6- tetragalloylglucopyranoside leads only to coupling at the O(4)/O(6) galloyls. Competitive oxidation experiments with a series of positionally distinct phenolic galloyl analogs furnishes evidence that this unexpected regioselectivity stems from preferential oxidation at the O(6) galloyl ring. Companion studies with electronically dissimilar analogs provide support for a through-space component to O(6) galloyl oxidation selectivity in addition to steric and inductive influences.