Synthesis of 3,4,5‐Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates by an NaNO2/I2‐Mediated Domino Reaction |
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| Authors: | Shashikant U. Dighe Sushobhan Mukhopadhyay Shivalinga Kolle Dr. Sanjeev Kanojiya Sanjay Batra |
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| Affiliation: | 1. Medicinal and Process Chemistry Division, CSIR‐Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031 (India);2. Sophisticated Analytical Instrumentation Facility, CSIR, Central Drug Research Institute (India);3. Academy of Scientific and Innovative Research, New Delhi (India);4. Academy of Scientific and Innovative Research, New Delhi (India)Medicinal and Process Chemistry Division, CSIR‐Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031 (India) |
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| Abstract: | An efficient NaNO2/I2‐mediated one‐pot transformation of Morita–Baylis–Hillman (MBH) acetates into alkyl 3‐nitro‐5‐(aryl/alkyl)isoxazole‐4‐carboxylates is described. In a cascade event, initial Michael addition of NaNO2 to the MBH acetate furnishes the allylnitro intermediate which undergoes I2‐catalyzed oxidative α‐C H nitration of the nitromethyl subunit followed by [3+2] cycloaddition to afford the title compounds. Structural elaborations of these highly substituted isoxazoles by SNAr reactions and hydrogenolysis allows access to useful products. |
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| Keywords: | C‐H‐Aktivierung Cyclisierungen Heterocyclen Iod Michael‐Addition |
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