A Photorearrangement To Construct the ABDE Tetracyclic Core of Palau'amine.

A synthesis of the ABDE tetracyclic carbon core of palau'amine was achieved in 9 steps from commercial materials. The core's most notable feature, a highly strained trans cyclopenta[ c]pyrrolidine, was obtained in high yield using a ring contraction strategy starting from a much less strained trans bicyclic lactam derivative that is accessible in only 7 steps.