title: Catalytic asymmetric intermolecular stetter reaction of heterocyclic aldehydes with nitroalkenes: backbone fluorination improves selectivity.
abstract: The catalytic asymmetric intermolecular Stetter reaction of heterocyclic aldehydes and nitroalkenes has been developed. We have identified a strong stereoelectronic effect on catalyst structure when a fluorine substituent is placed in the backbone. X-ray structure analysis provides evidence that hyperconjugative effects are responsible for a change in conformation in the azolium precatalyst. This new N-heterocyclic carbene precursor bearing fluorine substitution in the backbone results in significantly improved enantioselectivities across a range of substrates.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: DiRocco
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Oberg
authors.forename: Derek M
authors.initials: DM
authors.lastname: Dalton
authors.forename: Tomislav
authors.initials: T
authors.lastname: Rovis
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D054879:Halogenation; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry*; D055601:Organic Chemistry Phenomena; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000475:Alkenes; D009574:Nitro Compounds