Iron-Catalyzed Intramolecular Perezone-Type [5 + 2] Cycloaddition: Access to Tricyclo[6.3.1.01,6]dodecane

Article abstract of DOI:10.1021/acs.orglett.8b00989

An iron-catalyzed perezone-type [5 + 2] cycloaddition toward tricyclo[6.3.1.0^1,6]dodecane scaffolds is presented, furnishing cycloadducts with two new C-C bonds and three to four stereogenic centers generated with typically good yields and excellent diastereoselectivities. Two independent conditions, catalytic FeCl₃/PhCO₃tBu (0.5 equiv/1 equiv) and stoichiometric FeCl₃(2 equiv), have been respectively manifested to be applicable for various substrates. Mechanistically, the reaction may proceed via iron-mediated generation of a carbon cationic center, which triggers subsequent [5 + 2] cyclization. Derivation of the cycloadduct was conducted to testify the applicability of this method.