An efficient synthesis of (±)-epigallocatechin gallate by reductive intramolecular etherification

The synthesis of (±)-epigallocatechin gallate by direct cyclization to the cis-3-acyloxy-2-arylbenzopyranee is described. α-Acyloxylketones, possessing a 2-hydroxylphenyl group at the β-position, underwent intramolecular reductive etherification to give cis-3-acyloxy-2-arylbenzopyran due to neighboring group participation of the acyloxyl group at the α-position. Using this method, we accomplished the stereoselective synthesis of (±)-epigallocatechin gallate.