Unprecedented and Scalable Copper (I)-Catalyzed Oxidation of the Csp2-H bond on 2-phenyl-naphthalene-1,3-diol with Atmospheric Oxygen: synthesis of 2-Hydroxy-3-phenyl-1,4-naphthoquinone via direct Csp2-O bond formation
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Keywords

Oxidation of naphthol
oxidative dimerization of phenols
1
4-naphthoquinone
ningalin D.

Abstract

The Csp2-O bond formation via direct oxidation of the Csp2-H bond on electron-rich compounds such as naphthols, is a process that generally requires drastic reaction conditions like high temperature or pressure. Addition of strong oxidants as H2O2, hypervalent iodine reagents (λ3 o λ5), expensive transition metals or rare earth elements, such as Mo, Ru Pt or Ce, is usually necessary. As part of this study on oxidative dimerization of phenols towards the total synthesis of ningalin D, 1,3-naphthalenediol was explored as starting material using stoichiometric amounts of Cu(I) and atmospheric molecular oxygen. A novel two-step sequence reaction for the formation of a 1,4-naphthoquinone was found instead of a dimerization product. The synthesis of this compound involves two consecutive oxidation processes. 

https://doi.org/10.15174/au.2017.1337
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