Abstract: Processes for preparing racemic mixtures of 5,7,3?,4?-tetra-O-benzyl-(±)-catechin and (±)-epicatechin involves (i) condensing 2-hydroxy-4,6-bis(benzyloxy)-acetophenone and 3,4-bis(benzyloxy)benzaldehyde, cyclizing the resulting compound, oxidizing the resulting compound; (ii) dihydroxylating (E)-3-(3?,4?-bis(benzyloxy)phenyl)prop-2-ene-1-ol and reducing the 1,2-diol; or (iii) coupling 3,5-bis(benzyloxy)phenol with (E)-3,5-bis(benzyloxy)-2-(3?,4?-bis(benzyloxy)phenyl)allyl)phenol and cyclizing the resulting chalcone. A process for preparing the benzylated epimers of catechin and epicatechin involves seven steps. 3,4-Bis(benzyloxy)benzaldehyde is coupled with 2-hydroxy-4,6-benzyloxy-acetophenone to form a chalcone. The chalcone is selectively reduced to an alkene. The phenolic group of the alkene is protected. The protected alkene is asymetrically dihydroxylated. The resulting compound is deprotected, cyclized, and finally hydrolyzed.

Abstract: Improved processes for the preparation of tetra-O-benzyl protected catechin, for the coupling of the tetra-O-benzyl protected catechin or epicatechin with a C-4 activated, tetra-O-benzyl protected epicatechin for the galloylation of the epicatechin-(4?,8)-catechin or -epicatechin dimer-the dimer digallates, and for the deprotection (i.e., debenzylation) of the protected epicatechin dimers and protected epicatechin dimer digallates are disclosed.