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Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Functional Group Migration-Driven Quaternary Carbon Editing via Intramolecular [4+2] Annulation
Yi-Xin Xing1, Bo-Xi Liu1, Feng Zhou1
1Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou215123, China.
Abstract:
A photocatalytic tandem radical intramolecular [4+2] cyclization of unactivated cyanated alkenes for constructing functionalized benzo[1,6]naphthyridinones through the integration of radical cyano migration and hydrogen atom transfer (HAT) strategies is reported. This protocol uses mild reaction conditions, readily accessible and stable substrates, and a metal-free organic photocatalyst while enabling late-stage functionalization. The mechanistic study reveals that the intramolecular [4+2] cyclization mechanism involves radical addition to an unactivated alkene, followed by 1,4-cyano migration, 1,6-HAT, and a subsequent intramolecular 6-endo-trig radical cyclization process.
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