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Enantioselective Alkynylation of Trifluoromethyl Ketones Catalyzed by Cation-Binding Salen Nickel Complexes |
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| Authors: | Dongseong Park Carina I Jette Jiyun Kim Woo-Ok Jung Yongmin Lee Jongwoo Park Seungyoon Kang Min Su Han Brian M Stoltz Sukwon Hong |
| Institution: | 1. Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005 Republic of Korea
These authors contributed equally to this work.;2. Warren And Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125 USA These authors contributed equally to this work.;3. Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005 Republic of Korea;4. School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-gwagiro Buk-gu, Gwangju, 61005 Republic of Korea;5. Department of Chemistry, University of Florida, P.O.Box 117200, Gainesville, FL, 32611-7200 USA Current address: Process R&D Center, SK biotek, 325 Exporo, Yuseong-gu, Daejeon, 34124 Republic of Korea;6. Warren And Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125 USA |
| Abstract: | Cation-binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99 %) and high enantioselectivity (up to 97 % ee). The reaction proceeds with substoichiometric quantities of base (10–20 mol % KOt-Bu) and open to air. In the case of trifluoromethyl vinyl ketones, excellent chemo-selectivity was observed, generating 1,2-addition products exclusively over 1,4-addition products. UV-vis analysis revealed the pendant oligo-ether group of the catalyst strongly binds to the potassium cation (K+) with 1:1 binding stoichiometry (Ka=6.6×105 m −1). |
| Keywords: | Alkinylierung Bifunktionelle Katalyse Nickel Trifluormethylketone |