Synthesis of procyanidins by stepwise- and self-condensation using 3,4-cis-4-acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-benzyl-(+)-catechin and (−)-epicatechin as a key building monomer. - Oyama,K-I.; Kuwano,M.; Ito,M.; Yoshida,K.; Kondo,T. (Tetrahedron Lett, 2008)