Total synthesis of Oenothein C

The simple total synthesis of oenothein C (1), ellagitannin, originally isolated from the leaves of Oenothera erythrosepala, was achieved by successive esterification of the glucose derivative with the protected valoneic acid dilactone (2) and gallic acid (3). The lactonized valoneic acid (11), which is the key structural part, was prepared by the intermolecular Ullmann cross coupling reaction.