4378-02-3Relevant articles and documents
Rapid access to halohydrofurans via bronsted acid-catalyzed hydroxylation/halocyclization of cyclopropyl methanols with water and electrophilic halides
Mothe, Srinivasa Reddy,Kothandaraman, Prasath,Rao, Weidong,Chan, Philip Wai Hong
experimental part, p. 2521 - 2531 (2011/05/14)
A one-pot, two-step method to prepare 3-halohydrofurans efficiently by TfOH-catalyzed hydroxylation/halocyclization of cyclopropyl methanols with H2O 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 Bronsted 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.
Synthesis of (Z,E)- and (Z,Z)-α-Farnesenes and -Homofarnesenes
Morgan, E. David,Thompson, Lorna D.
, p. 399 - 404 (2007/10/02)
The ant substance (Z,E)-α-farnesene and its isomer (Z,Z)-α-farnesene have been synthesized in an overall yield of 34percent in six stages from methyl cyclopropyl ketone and 6-methylhept-5-en-2-one via a Wittig condensation.A mixture of the corresponding (Z,E)-α-homofarnesene of ants and its (Z,Z) isomer were prepared in much poorer yield by the same method and incompletely characterized.The isomeric identification of both insect materials were confirmed.
