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O-Benzyl Xanthate Esters under Ni/Photoredox Dual Catalysis: Selective Radical Generation and Csp(3)–Csp(2) Cross-Coupling

[Image: see text] Alkyl xanthate esters are perhaps best known for their use in deoxygenation chemistry. However, their use in cross-coupling chemistry has not been productive, which is due, in part, to inadequate xanthate activation strategies. Herein, we report the use of O-benzyl xanthate esters,...

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Detalles Bibliográficos
Autores principales: Vara, Brandon A., Patel, Niki R., Molander, Gary A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5460664/
https://www.ncbi.nlm.nih.gov/pubmed/28603657
http://dx.doi.org/10.1021/acscatal.7b00772
Descripción
Sumario:[Image: see text] Alkyl xanthate esters are perhaps best known for their use in deoxygenation chemistry. However, their use in cross-coupling chemistry has not been productive, which is due, in part, to inadequate xanthate activation strategies. Herein, we report the use of O-benzyl xanthate esters, readily derived from alcohols, as radical pronucleophiles in Csp(3)–Csp(2) cross-couplings under Ni/photoredox dual catalysis. Xanthate (C–O) cleavage is found to be reliant on photogenerated (sec-butyl) radical activators to form new carbon-centered radicals primed for nickel-catalyzed cross-couplings. Mechanistic experiments support the fact that the key radical components are formed independently, and relative rates are carefully orchestrated, such that no cross reactivity is observed.