Total synthesis of dipiperamide A and revision of stereochemical assignment

The first total synthesis of dipiperamide A has been achieved by employing a solid-state photodimerization of an (E)-cinnamic acid derivative. This critical step results in the cyclobutane ring, which exists in the natural product, with full control of the regio- and stereochemistry at the four stereogenic centers. Results from these studies indicate that the proposed stereostructure of natural dipiperamide A should be revised to the structure originally assigned to dipiperamide B.