title: Resolution of racemic 2-aminocyclohexanol derivatives and their application as ligands in asymmetric catalysis.
abstract: A preparatively easy and efficient protocol for the resolution of racemic 2-aminocyclohexanol derivatives is described, delivering both enantiomers with >99% enantiomeric excess (ee) by sequential use of (R)- and (S)-mandelic acid. A simple aqueous workup procedure permits the isolation of the amino alcohols in analytically pure form and the almost quantitative recovery of mandelic acid. Debenzylation of enantiopure trans-2-(N-benzyl)amino-1-cyclohexanol by hydrogenation and subsequent derivatization give access to a broad variety of diversely substituted derivatives. Furthermore, the corresponding cis isomers are readily available. Applications of these optically active aminocyclohexanols in catalyzed asymmetric phenyl transfer reactions to benzaldehydes and transfer hydrogenations of aryl ketones lead to products with up to 96% ee.
authors.affiliation: Institut für Organische Chemie der RWTH Aachen, Landoltweg 1, D-52056 Aachen, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Schiffers
authors.forename: Toni
authors.initials: T
authors.lastname: Rantanen
authors.forename: Frank
authors.initials: F
authors.lastname: Schmidt
authors.forename: Werner
authors.initials: W
authors.lastname: Bergmans
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zani
authors.forename: Carsten
authors.initials: C
authors.lastname: Bolm
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D001547:Benzaldehydes / Q000737:chemistry*; D002384:Catalysis; D003511:Cyclohexanols / Q000138:chemical synthesis / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry; D008024:Ligands; D008333:Mandelic Acids / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: C516358:2-aminocyclohexanol; D000438:Alcohols; D001547:Benzaldehydes; D003511:Cyclohexanols; D007659:Ketones; D008024:Ligands; D008333:Mandelic Acids; C037938:mandelic acid