Furans and their Benzo Derivatives: Structure

Senning, A.

doi:10.1016/b978-008044992-0.00305-9

Cited by 3 publications

References 113 publications

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Rapid Access to Halohydrofurans via Brønsted Acid-Catalyzed Hydroxylation/Halocyclization of Cyclopropyl Methanols with Water and Electrophilic Halides

et al. 2011

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A one-pot, two-step method to prepare 3-halohydrofurans efficiently by TfOH-catalyzed hydroxylation/halocyclization of cyclopropyl methanols with H(2)O and N-halosuccinimide (NXS, X=1, Br, Cl) or Selectfluor is described. The reactions proceed rapidly under mild and operationally straightforward conditions with a catalyst loading as low as 1 mol % and afford the 3-halohydrofuran products in moderate to excellent yields and, in most cases, with preferential cis diastereoselectivity. The method was shown to be applicable to cyclopropyl methanols containing electron-withdrawing, electron-donating, and sterically demanding functional groups and electrophilic halide sources. The mechanism is suggested to involve protonation of the alcohol substrate by the Brønsted acid catalyst and ionization of the starting material. This results in ring-opening of the cyclopropane moiety and in situ formation of a homoallylic alcohol intermediate, which undergoes subsequent intramolecular halocyclization on treating with the electrophilic halide source to give the halohydrofuran. The observed cis product selectivity is thought to be determined by the reaction proceeding through an in situ generated unsaturated alcohol intermediate that contains a (Z)-alkene moiety under the kinetically controlled conditions.

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Rapid Access to Halohydrofurans via Brønsted Acid-Catalyzed Hydroxylation/Halocyclization of Cyclopropyl Methanols with Water and Electrophilic Halides

et al. 2011

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9.9.6 Furans (Update 2024)

Kwiecień

2024

Knowledge Updates 2024/3

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This review is an update to the earlier Science of Synthesis contributions presenting methods for the synthesis of furans. It focuses on the literature published between 2011 and 2022. In the last decade, a number of new methods for the synthesis of furans from acyclic functionalized molecules have been developed. Many of the methods are based on (mixed) transition-metal catalysis, which induces several combinations of isomerizations, rearrangements, and cyclizations, leading to reactions that are termed cycloisomerizations. Multicomponent reactions for the synthesis of furans are also included.

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