Reagent-controlled stereoselective synthesis of (±)-gallo- and (±)-epigallo-catechin gallates

Synthesis of (±)-gallocatechin and (±)-epigallocatechin gallates by electrophilic cycloarylation is reported. The precursors for cyclization were prepared by reagent-controlled stereo-selective opening of epoxide with phenol. Activation of the S-oxidized S,O-acetal enabled electrophilic cycloarylation to stereoselectively provide the acylated catechins.