2-Substituted-2, 7, 9-decatrienoates undergo an iron-catalyzed carbocyclization to yield trans-disubstituted cyclopentanes in moderate-to-good chemical yields. The cyclization products are formally the result of a [4+ 4]-ene reaction in which cis-propenyl and 2-acroyl functionalities are introduced as appendages to the newly formed cyclopentane ring by the cyclization. Triene ester substrates bearing an alkyl substituent at the 4-or 6-positions ...