Catalytic Enantioselective Conjugate Alkynylation of α,β‐Unsaturated 1,1,1‐Trifluoromethyl Ketones with Terminal Alkynes |
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Authors: | Dr. Amparo Sanz‐Marco Prof. Dr. Gonzalo Blay Prof. Dr. M. Carmen Muñoz Prof. Dr. José R. Pedro |
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Affiliation: | 1. www.uv.es 0000-0002-1729-598X Department de Química Orgànica-Facultat de Química, Universitat de València, Burjasso, Spain;2. Department de Química Orgànica-Facultat de Química, Universitat de València, Burjasso, Spain;3. Departament de Física Aplicada, Universitat Politècnica de València, València, Spain;4. (+34)?963544328 0000-0002-6137-866X Department de Química Orgànica-Facultat de Química, Universitat de València, Burjasso, Spain |
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Abstract: | The first catalytic enantioselective conjugate alkynylation of α,β‐unsaturated 1,1,1‐trifluoromethyl ketones has been carried out. Terminal alkynes and 1,3‐diynes were treated with trifluoromethyl ketones in the presence of a low catalytic load of a CuI‐MeOBIPHEP complex (2.5 mol %) and triethylamine (10 mol %) to give the corresponding trifluoromethyl ketones bearing a propargylic stereogenic center at the β position with good yields and excellent enantiomeric excesses in most of the cases. No 1,2‐addition products were formed under the reaction conditions. The procedure showed broad substrate scope for alkyne, diyne, and enone. A rationale for the observed stereochemistry has been provided. Finally, the potential application of the reaction products in the synthesis of chiral tetrahydrofurans bearing a trifluoromethylated quaternary stereocenter has been devised. |
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Keywords: | alkynes asymmetric catalysis conjugate addition enones fluorine |
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