title: Highly diastereoselective reductive coupling of 2-bromo-2,3,3,3-tetrafluoropropanamide with aldehydes promoted by triphenylphosphine-titanium(IV) isopropoxide. An efficient route to the synthesis of erythro-alpha-fluoro-alpha-(trifluoromethyl)-beta-hydroxy amides.
abstract: The reductive coupling reaction of N-methoxy-N-methyl-2-bromo-2,3,3,3-tetrafluoropropanamide (Weinreb amide) with various aldehydes under the influence of the combined reagent, 1.2 equiv each of triphenylphosphine and titanium(IV) isopropoxide, took place smoothly at ambient temperature to give the corresponding alpha-fluoro-alpha-(trifluoromethyl)-beta-hydroxy amides in a highly erythro-selective manner. The high erythro selectivity was also obtained even by employing a combination of triphenylphosphine (1.2 equiv) and a catalytic amount of titanium(IV) isopropoxide.
authors.affiliation: Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Sekiguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishihara
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Konno
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamanaka