title: Regioselective dihalohydration reactions of propargylic alcohols: gold-catalyzed and noncatalyzed reactions.
abstract: The regioselective conversion of propargylic alcohols into previously unreported α,α-diiodo-β-hydroxyketones was achieved by treatment with N-iodosuccinimide in the presence of a gold catalyst. The corresponding α,α-dichloro-β-hydroxyketones were obtained by treatment with trichloroisocyanuric acid in the absence of a catalyst. The latter reaction can be extended to other alkynols. These transformations can be used to prepare potentially useful halogenated building blocks. Preliminary mechanistic studies suggest that the reaction involves participation of the acetonitrile solvent in the formation of a 5-halo-1,3-oxazine intermediate.
authors.affiliation: Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ (UK) http://www.tomsheppard.eu.
authors.forename: Jarryl M
authors.initials: JM
authors.lastname: D'Oyley
authors.forename: Abil E
authors.initials: AE
authors.lastname: Aliev
authors.forename: Tom D
authors.initials: TD
authors.lastname: Sheppard
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D054879:Halogenation; D007659:Ketones / Q000737:chemistry*; D020005:Propanols / Q000737:chemistry*; D013237:Stereoisomerism; D013388:Succinimides / Q000737:chemistry*
chemical_list: D000480:Alkynes; D007659:Ketones; D020005:Propanols; D013388:Succinimides; C008155:N-iodosuccinimide; D006046:Gold; C028255:propargyl alcohol
keywords: gold; halogenation; homogeneous catalysis; ketones; reaction mechanisms