title: Alpha-fluoro-alpha-nitro(phenylsulfonyl)methane as a fluoromethyl pronucleophile: efficient stereoselective Michael addition to chalcones.
abstract: Highly efficient stereoselective 1,4-addition of racemic alpha-fluoro-alpha-nitro(phenylsulfonyl)methane (FNSM) as a fluoromethyl pronucleophile to alpha,beta-unsaturated ketones using a wide range of chiral organobifunctional catalysts under moderate conditions in the absence of an additional base has been achieved. A series of catalysts was screened for the enantioselective addition of FNSM to chalcones and the catalysts CN I, CD I, QN I-IV, and QD I were found to enable this reaction, successfully providing exclusive 1,4-addition products stereoselectively in high yields (conversion, diastereomeric ratio, and enantiomeric excess). Studies involving a model reaction and systematic analysis of the absolute configuration support the suggested mechanism.
authors.affiliation: Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, CA 90089-1661, USA. gprakash@usc.edu
authors.forename: G K Surya
authors.initials: GK
authors.lastname: Prakash
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Timothy
authors.initials: T
authors.lastname: Stewart
authors.forename: Thomas
authors.initials: T
authors.lastname: Mathew
authors.forename: George A
authors.initials: GA
authors.lastname: Olah
mesh_terms: D047188:Chalcones / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D047188:Chalcones; D006845:Hydrocarbons, Fluorinated; C029999:fluoromethane