Reactivity of α-diazo sulfonium salts: rhodium-catalysed ring expansion of indenes to naphthalenes

Abstract

Cyclopropyl-substituted sulfonium salts are obtained by Rh-catalysed addition of α-diazo dibenzothiophenium salts to olefins. When indenes are used as substrates, initially formed cyclopropyl rings open with concomitant elimination of dibenzothiophene, enabling access to 2-substituted naphthalenes.