Thermal Rearrangements and Reactions of 5-Alkyl-1,2,3,4,5-pentakis(methoxycarbonyl)cyclopentadienes

Article abstract of DOI:10.1021/jo00081a029

Studies of the thermal reactions of five 5-alkyl-1,2,3,4,5-pentakis(methoxycarbonyl)cyclopentadienes in methanol solvent are described, where the alkyl groups are benzhydryl, methoxymethyl, 1-adamantyl, p-methoxybenzyl, and benzyl.The benzyl cyclopentadiene system undergoes thermal <1,5>-sigmatropic rearrangement via methoxycarbonyl migrations while the other cyclopentadienes undergo C-alkyl bond heterolysis to ion-pair intermediates, which are scavenged by solvent.First-order rate constants for solvolysis of the methoxymethyl, 1-adamantyl, and p-methoxymethyl systems in methanol solvent were determined and that for the benzhydryl system was estimated from a single measurement of the half-life.