- Rh-Catalyzed Reactions of 1,4-Benzoquinones with Electrophiles: C-H Iodination, Bromination, and Phenylselenation
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Under Rh-catalyzed conditions, typically electrophilic 1,4-benzoquinones exhibit nucleophilic reactivity, such that exposure to appropriate electrophiles generates products of C-H iodination, bromination, and phenylselenation. This provides a mild and general method for direct halofunctionalization, and the first method that can achieve direct C-H phenylselenation of this compound class. The scope and limitations of the new protocols are outlined, and representative derivatizations are highlighted.
- Jardim, Guilherme A. M.,Bower, John F.,Da Silva Júnior, Eufranio N.
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p. 4454 - 4457
(2016/09/28)
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- Formation of dimer-type ketals in the reaction of 2,4,6-trichlorophenol and 2,4,6-trichloro-m-cresol with calcium hypochlorite in methanol: Conversion to quinones and other compounds
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2,4,6-Trichlorophenol (2) and 2,4,6-trichloro-m-cresol (5) react with calcium hypochlorite (Ca(OCl)2) in MeOH to give respectively dimer-type ketals 2-(2′,4′,6′-trichlorophenoxy)-4,4-dimethoxy-6 -chlorocyclohexadien-2,5-one (6) and 2-(3′-methyl-2′,4′,6′-trichlorophenoxy)-4, 4-di-methoxy-5-methyl-6-chlorocyclohexadien-2,5-one (7). Ketal 6, which was too unstable to be isolated, and 7 hydrolyzed in H2O/HCl to 2-(2′,4′,6′-trichlorophenoxy)-6-chloro-1,4-ben-zoquinone (8) and 2-(3′-methyl-2′,4′,6′-trichlorophenoxy)-5 -methyl-6-chloro-1,4-benzoquinone (9), respectively. Ketal 6 and quinone 8 were also produced when 2 and Ca(OCl)2 reacted in DMF, followed by addition of MeOH and H2O, respectively. The mechanisms of these reactions are examined. Conversion of the ketals and quinones to other products is described.
- Heasley, Victor L.,Anderson, James D.,Bowman, Zachery S.,Hanley Jr., John C.,Sigmund, Geoffery A.,Van Horn, David,Shellhamer, Dale F.
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p. 6827 - 6830
(2007/10/03)
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- A New Route to Isodityrosine-derived Cyclic Peptides: Application to K-13
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A versatile approach suitable for isodityrosine-derived cyclic peptides, and its application to K-13 have been described.
- Rao, A. V. Rama,Gurjar, Mukund K.,Reddy, A. Bhaskar,Khare, Vivek, B.
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p. 1657 - 1660
(2007/10/02)
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