Studies in the Cycloproparene Series: The Behavior of Alkylidenecycloproparenes Towards Nucleophiles and Oxidizing Agents

Abstract

The alkylidenecycloproparene (1) reacts with potassium t- butoxide to give the ring-expanded heptafulvene (3). Epoxidation of (1) provides the hydroxy ketone (5) probably via the spiro epoxide (4) but carbene additions fail to give spirocycle (7). Photooxygenation of (1a,b) gives products (5),(12)-(14) and (16) which are explicable in terms of initial formation of dioxetan (10); products (13) and (14) result from 1H-cyclopropa[b] naphthalenone (11). By comparison (1c) provides phenanthraquinone acetal (17) in low yield. With osmium tetroxide and sodium periodate , (1a) gives benzophenone (12a) in competition with hydroxy ketone (5a) and 2,2-diphenylcyclobutanaphthalenone (20). The modes of formation of the various products are discussed.