Selective,Transition Metal-free 1,2-Diboration of Alkyl Halides,Tosylates, and Alcohols |
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Authors: | Mingming Huang Dr. Jiefeng Hu Shasha Shi Dr. Alexandra Friedrich Johannes Krebs Prof. Dr. Stephen A. Westcott Prof. Dr. Udo Radius Prof. Dr. Todd B. Marder |
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Affiliation: | 1. Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany;2. School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816 China;3. Department of Chemistry & Biochemistry, Mount Allison University, Sackville, NB E4L 1G8 Canada |
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Abstract: | Defunctionalization of readily available feedstocks to provide alkenes for the synthesis of multifunctional molecules represents an extremely useful process in organic synthesis. Herein, we describe a transition metal-free, simple and efficient strategy to access alkyl 1,2-bis(boronate esters) via regio- and diastereoselective diboration of secondary and tertiary alkyl halides (Br, Cl, I), tosylates, and alcohols. Control experiments demonstrated that the key to this high reactivity and selectivity is the addition of a combination of potassium iodide and N,N-dimethylacetamide (DMA). The practicality and industrial potential of this transformation are demonstrated by its operational simplicity, wide functional group tolerance, and the late-stage modification of complex molecules. From a drug discovery perspective, this synthetic method offers control of the position of diversification and diastereoselectivity in complex ring scaffolds, which would be especially useful in a lead optimization program. |
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Keywords: | 1,2-diboration boron boronate 1,2-diborylalkanes metal-free |
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