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Al Beiruty H, Zhylinska SS, Kutateladze N, Cheong HKT, Ñíguez JA, Burlingham SJ, Marset X, Guillena G, Chinchilla R, Alonso DA, Nugent TC. Enantioselective Catalytic Aldol Reactions in the Presence of Knoevenagel Nucleophiles: A Chemoselective Switch Optimized in Deep Eutectic Solvents Using Mechanochemistry. Molecules 2023; 29:4. [PMID: 38202587 PMCID: PMC10779746 DOI: 10.3390/molecules29010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/06/2023] [Accepted: 12/10/2023] [Indexed: 01/12/2024] Open
Abstract
In the presence of different nucleophilic Knoevenagel competitors, cyclic and acyclic ketones have been shown to undergo highly chemoselective aldol reactions with aldehydes. In doing so, the substrate breadth for this emerging methodology has been significantly broadened. The method is also no longer beholden to proline-based catalyst templates, e.g., commercially available O-t-Bu-L-threonine is advantageous for acyclic ketones. The key insight was to exploit water-based mediums under conventional (in-water) and non-conventional (deep eutectic solvents) conditions. With few exceptions, high aldol-to-Knoevenagel chemoselectivity (>10:1) and good product profiles (yield, dr, and ee) were observed, but only in DESs (deep eutectic solvents) in conjunction with ball milling did short reaction times occur.
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Affiliation(s)
- Hanaa Al Beiruty
- School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
| | | | - Nino Kutateladze
- School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
| | | | - José A. Ñíguez
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Sarah J. Burlingham
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Xavier Marset
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Gabriela Guillena
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Rafael Chinchilla
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Diego A. Alonso
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain (G.G.); (R.C.)
| | - Thomas C. Nugent
- School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
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