Synthesis of Enantiomerically Pure Unusual Ellagitannins 1,4,6-Tri- O -galloyl-2,3-( R )-hexahydroxydiphenoyl-β- d -glucopyranoside and 4,6-Di- O -galloyl-2,3-( R )-hexahydroxydiphenoyl- d -glucoside. The Proposed Chemical Structures for Cercidinin A and B Must Be Revised