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![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Photocatalytic 1,6-HAT-Enabled Formal [3 + 3] Annulation of Vinyl Azides with α-Bromomalonates to Tetrahydropyridines
Wen-Jun Li1, Li-Fa Zhong1, Limin Yang2
1Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou215123, China.
Abstract:
A visible-light-induced formal [3 + 3] annulation of vinyl azides with branched alkyl-substituted α-bromomalonates is reported for the synthesis of polysubstituted 2,3,4,5-tetrahydropyridines. Photocatalytic generation of a carbon-centered radical, followed by addition to the vinyl azide and N2 extrusion, affords an iminyl radical that undergoes 1,6-HAT and cyclization. The reaction proceeds under mild conditions, exhibits broad substrate compatibility, and is amenable to gram-scale synthesis. Hydrogenation of the products provides highly substituted piperidines, demonstrating the synthetic utility of the method.
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