Ionic Liquids as Precatalysts in the Highly Stereoselective Conjugate Addition of α,β‐Unsaturated Aldehydes to Chalcones |
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Authors: | Joachim Bijl Prof Matti Haukka Dr Henrik Sundén |
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Institution: | 1. Chemistry and Biological Engineering, Chalmers University of Technology, Kemiv?gen 10, 412 96 Gothenburg (Sweden);2. Department of Chemistry, University of Jyv?skyl?, P.O. Box 35, FI‐40014 University of Jyv?skyl?, Finland. |
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Abstract: | Imidazolium‐based ionic liquids (ILs) serve both as recyclable reaction media and as precatalysts for the N‐heterocyclic carbene‐catalyzed conjugate addition of α,β‐unsaturated aldehydes to chalcones. The reaction produces a broad scope of 1,6‐ketoesters incorporating an anti‐diphenyl moiety in high yields and with high stereoselectivity. In recycling experiments, the IL can be reused up to five times with retained reactivity and selectivity. Moreover, the 1,6‐ketoesters form self‐assembled organogels in aliphatic hydrocarbons. The reaction protocol is robust, easily operated, scalable and highly functionalized compounds can be obtained from inexpensive and readily accessible starting materials. |
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Keywords: | green chemistry ketoesters ionic liquids NHC organogels |
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