title: Iron(III)-Catalyzed Cycloisomerizations of Acetal-Vinylidenecyclopropanes: An Efficient Synthetic Route to 1,2-Disubstituted Cyclobutenes.
abstract: A novel iron(III)-catalyzed intramolecular cycloisomerization of acetal-vinylidenecyclopropanes to afford a series of halogenated 1,2-disubstituted cyclobutenes tethered with a tetrahydropyrrole has been developed. The reaction is thought to proceed through a formal iron-catalyzed Prins cyclization followed by a ring-enlarging rearrangement of the methylenecyclopropane carbocation. The present protocol provides an alternative route to functionalized disubstituted cyclobutenes and the corresponding products could be successfully transformed into eight-membered oxacyclic products.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (P. R. China).
authors.forename: Song
authors.initials: S
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (P. R. China).
authors.forename: Wei
authors.initials: W
authors.lastname: Yuan
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (P. R. China).
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (P. R. China). mshi@mail.sioc.ac.cn.|State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (P. R. China).. mshi@mail.sioc.ac.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Shi
keywords: cycloisomerization; homogeneous catalysis; iron; ring expansion; small ring systems