SYNTHETIC STUDIES ON ZOAPATANOL - CONSTRUCTION OF OXEPANES VIA AN INTRAMOLECULAR 1,3-DIPOLAR CYCLOADDITION STRATEGY

The nitrones derived from beta-allyloxyaldehydes with a beta-quaternar y centre cyclized to give six- instead of seven-membered O-heterocycle s exclusively whereas a nitrile oxide derived from a gamma-allyloxyald ehyde with a gamma-quaternary centre cyclized to yield an oxepane ring as the sole product. Using the latter intramolecular nitrile oxide cy cloaddition as the key step, optically active oxepane 5, which is a su itable intermediate for a synthesis of zoapatanol 1, has been construc ted from D-glucose. Copyright (C) 1996 Elsevier Science Ltd