title: Remarkably Facile Borane-Promoted, Rhodium-Catalyzed Asymmetric Hydrogenation of Tri- and Tetrasubstituted Alkenes.
abstract: Oxime-directed catalytic asymmetric hydroboration is diverted to catalytic asymmetric hydrogenation (CAH) upon the addition of a proton source, such as MeOH, or by running the reaction under a hydrogen atmosphere. A borane (e.g., pinacolborane) is required to promote CAH. Tri- and tetrasubstituted alkenes, including the challenging all-alkyl tetrasubstituted alkenes, undergo CAH with enantiomer ratios (er) as high as 99:1. The mild reaction conditions, i.e., ambient temperature, moderate reaction times, and the need for only a slight excess of H2, contrast those used in most state-of-the-art catalysts for related substrates.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States.
authors.forename: Veronika M
authors.identifier: 0000-0003-0402-7414
authors.initials: VM
authors.lastname: Shoba
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States.
authors.forename: James M
authors.identifier: 0000-0002-1903-6535
authors.initials: JM
authors.lastname: Takacs
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D001880:Boranes / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D006865:Hydrogenation; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D001880:Boranes; D012238:Rhodium