Total synthesis of (±)-isodihydrokoumine, (±)-(19Z)-taberpsychine, and (±)-isodihydroukoumine N4 oxide

Jeff Kerkovius, The University of Western Ontario

Abstract

We report the total synthesis of the natural products (±)-isodihydrokoumine, and (±)-(19Z)-taberpsychine in 11 steps each, and (±)-isodihydrokoumine N₄-oxide in 12 steps from commercially available starting materials. The key reactions include an intramolecular [3+2] nitrone cycloaddition, and Lewis acid mediated cyclizations of a common intermediate to provide the core structures of either (19Z)-taberpsychine or isodihydrokoumine. Both failed and successful routes will be discussed.