Thermal rearrangements and reactions of 5-alkyl-1,2,3,4, 5-pentakis(methoxycarbonyl)cyclopentadienes

An analysis of the thermal rearrangements of five 5-alkyl-1,2,3,4,5-pentakis(methoxy carbonyl)-cyclopentadienes in methanol reveals that four cyclopentadiene systems dissociate into ion pairs due to C-C bond heterolysis. Benzyl cyclopentadiene rearranges through a concerted mechanism that involves methoxycarbonyl migration. The other four cyclopentadienes contain benzhydryl, methoxymethyl, 1-adamantyl and p-methoxybenzyl alkyl groups respectively.