title: Addition of bromine chloride and iodine monochloride to carbonyl-conjugated, acetylenic ketones: synthesis and mechanisms.
abstract: The reactions of 3-butyn-2-one (1), 3-hexyn-2-one (2), and 4-phenyl-3-butyn-2-one (3) with bromine chloride (BrCl) and iodine monochloride (ICl) in CH(2)Cl(2), CH(2)Cl(2)/pyridine, and MeOH are described. The data show that the major products in CH(2)Cl(2) are (Z)-AM (anti-Markovnikov) regioisomers. With the exception of 3 and ICl, the (E)-AM regioisomers predominate when pyridine was added as an acid scavenger. Minor amounts of the M regioisomers were formed with 1 and 2 and BrCl. The percentage of M regioisomer increased significantly with 1 and BrCl in MeOH, but MeOH had little affect on the other reactions. Isolation and stability of the products are discussed. Detailed evidence for the structures of the products, involving a combination of MS, (1)H and (13)C NMR, and IR, is presented; HRMS analyses are provided as proofs for all of the products. The acid-catalyzed mechanism and the halonium ion mechanism are considered as possible pathways in the formation of the products.
authors.affiliation: Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, USA. vheasley@ptloma.edu
authors.forename: Victor L
authors.initials: VL
authors.lastname: Heasley
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Buczala
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Chappell
authors.forename: David J
authors.initials: DJ
authors.lastname: Hill
authors.forename: Josh M
authors.initials: JM
authors.lastname: Whisenand
authors.forename: Dale F
authors.initials: DF
authors.lastname: Shellhamer