methyl cyanoacetate and 4-nitrobenzyl cyanide with 2-isopropyl-, 2-methyl-, and 2-phenyltropones in Ac2O gave isomeric 1-, 2-, and 3-substituted heptafulvene derivatives. The mechanism of reaction was explained in terms of a remote nucleophilic attack of the active methylene compounds to acetoxycycloheptatrienylium salt, followed by [1,5] sigmatropic hydrogen shift and elimination of acetic acid.