Quadricyclane-norbornadiene isomerizations on alumina

Abstract

Standard synthetic steps have been used to convert 7-methylenequadricyclane into the spiro-cyclopropene 1 and the allene 2. These (and other) quadricyclanes are cleanly isomerized on alumina to the respective bicyclo[2.2.1]hepta-2,5-dienes 3 and 4.