Short synthesis of berkeleyamide D and determination of the absolute configuration by the vibrational circular dichroism exciton chirality method.

The first synthesis of (±)-berkeleyamide D has been accomplished. The key features of this synthesis include the formation of an α,β-epoxy-γ-lactam via a Darzens reaction and the construction of a spirocyclic ring system by a C-acylation reaction followed by an intramolecular spirocyclization via an epoxide-opening reaction. Following optical resolution by chiral HPLC, the absolute configurations of both enantiomers of berkeleyamide D were determined by the vibrational circular dichroism exciton chirality method.