title: Design and development of highly effective Lewis acid catalysts for enantioselective Diels-Alder reactions.
abstract: This report describes the design and development of chiral Co(III)-salen catalysts for enantioselective Diels-Alder reactions. A crystal structure of a Co-salen catalyst with two equivalents of benzaldehyde provided insight on the factors that may be important for enantioselectivity. On the basis of this structural information, new catalysts were prepared in which the "bay region" tert-butyl groups were replaced by trimethylsilyl groups. The new silyl-substituted catalysts were exceptionally effective (catalyst loadings down to 0.05 mol %) and convenient to use-room temperature, under an air atmosphere, using a minimum amount of solvent.
authors.affiliation: Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois, 60637, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Iwama
authors.forename: Viresh H
authors.initials: VH
authors.lastname: Rawal
mesh_terms: D000171:Acrolein / Q000031:analogs & derivatives* / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005029:Ethylenediamines / Q000737:chemistry; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D005029:Ethylenediamines; D006844:Hydrocarbons, Cyclic; D009942:Organometallic Compounds; D003035:Cobalt; D000171:Acrolein; C011452:disalicylaldehyde ethylenediamine