Formation of 10b-bromomethyl-10c-methyl-10b,10c-dihydropyrenes from the corresponding [2.2]metacyclophanes

Abstract

2,7-Di-t-butyl-10b-halogenomethyl-10c-methyl-10b,10c-dihydropyrenes (2a) and (2b) were spontaneously formed when solutions of the corresponding 5,13-di-t-butyl-8-halogenomethyl-16-methyl[2.2]metacyclophanes (1a) and (1b) in CHCl₃ were left for a long time at room temperature; treatment of the [2.2] metacyclophanes (1a) and (1b) with bromine afforded the corresponding tetrabromo-10b,10c-dihydropyrenes (3a) and (3b).