Direct Asymmetric Michael Reactions of Cyclic 1,3-Dicarbonyl Compounds and Enamines Catalyzed by Chiral Bisoxazoline−Copper(II) Complexes
- 28 May 2003
- journal article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 68 (13), 5067-5074
- https://doi.org/10.1021/jo0343026
Abstract
The catalytic direct Michael addition of cyclic 1,3-dicarbonyl compounds and enamines to unsaturated 2-ketoesters is presented. A series of different 4-hydroxycoumarins, 4-hydroxy-6-methyl-2-pyrone, 3-hydroxy-1H-phenalene-1-one, 2-hydroxy-1,4-naphthoquinone, 5,5-dimethyl-1,3-cyclohexanedione, and various enamines of cyclic 1,3-diketones all add to unsaturated 4-substituted 2-ketoesters in an enantioselective manner. The reaction is catalyzed by chiral bisoxazoline−copper(II) complexes and proceeds in the absence of base to afford Michael adducts in good to high yields and with up to 98% ee. The products formed are substructures found in skeletons of important biological and pharmaceutical molecules. The scope and potential of the new reaction are discussed as well as the mechanism for the catalytic enantioselective reaction.Keywords
This publication has 18 references indexed in Scilit:
- A new method for enol lactone synthesis by a Michael addition/cyclization sequenceTetrahedron Letters, 2003
- Enantioselective conjugate additions of aldoximes to 3-crotonoyl-2-oxazolidinone and 1-crotonoyl-3-phenyl-2-imidazolidinone catalyzed by the aqua complex between R,R-DBFOX/Ph and zinc(II) perchlorateTetrahedron Letters, 2002
- An asymmetric approach to coumarin anticoagulants via hetero-Diels–Alder cycloadditionTetrahedron: Asymmetry, 2001
- Catalytic enantioselective alkylation of heteroaromatic compounds using alkylidene malonatesChemical Communications, 2001
- Chiral Lewis Acid Promoted Asymmetric Michael Addition Reaction of 2-(Trimethylsilyloxy)furansSynlett, 1997
- The first practical asymmetric synthesis of R and S-WarfarinTetrahedron Letters, 1996
- New Efficient Catalysts in the Synthesis of Warfarin and AcenocoumarolArchiv der Pharmazie, 1990
- The preferred solution conformation of warfarin at the active site of cytochrome P-450 based on the CD spectra in octanol/water model systemJournal of Medicinal Chemistry, 1984
- Studies on the Condensation Products of Some a,b-Unsaturated Carbonyl Compounds with 4-HydroxycoumarinHETEROCYCLES, 1984
- Studies on 4-Hydroxycoumarins. V. The Condensation of α,β-Unsaturated Ketones with 4-Hydroxycoumarin1Journal of the American Chemical Society, 1944