Synthesis of dihydrooxepin models related to the antitumor antibiotic MPC1001.

4-Hydroxy-L-proline was converted into the tetrahydrooxepino[4,3-b]pyrrole ring system characteristic of the potent antitumor agent MPC1001. Key steps were regioselective formation of a vinylogous amide by use of Bredereck's reagent and acid-induced cyclization of an alcohol onto the carbon-carbon double bond of that amide by addition-elimination to generate the seven-membered oxacyclic subunit.