Ring-opening reactions of cyclopropanes. Part 8. Nitrosation of donor-acceptor cyclopropanes

摘要

The reaction of 2,2-dialkoxycyclopropane-1-carboxylates 1a-d and monoalkoxycyclopropane 1e with NOCI gives isoxazoline- and/or isoxazole-3-carboxylates by regioselective ring-opening at C1-C2 bond. A mechanistic interpretation suggests the intermediacy of well-stabilised dipolar species.