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Only oxygen and acid! The oxidative coupling of xanthene and other activated benzylic compounds with carbon nucleophiles such as ketones, can be performed under ambient conditions without solvent by simply using oxygen and catalytic amounts of methanesulfonic acid. The proposed reaction mechanism involves substrate activation by formation of hydroperoxides; the method can therefore be regarded as an “autoxidative coupling reaction”.

Waste not wasted: A mechanistic study of the autoxidative coupling of xanthene with cyclopentanone uncovered an autoinductive effect of the waste product hydrogen peroxide. It generates radicals in the presence of acid and ketones, which accelerate the reaction by providing an additional pathway to the reactive hydroperoxide intermediate. This discovery could be applied to achieve other Brønsted acid-catalyzed oxidative coupling reactions

An aerobic organocatalytic oxidative CC bond formation reaction of benzylic CH bonds with various C-nucleophiles is described. The coupling reaction proceeds by simply stirring the substrates under elevated partial pressure of oxygen in the presence of a sulfonic acid catalyst at room temperature. Elevation of the pressure enables the reaction of a broad scope of nucleophile substrates otherwise showing poor reactivity at ambient pressure. The benzylic CH bonds of xanthene, acridanes, isochromane and related heterocycles could be functionalized with nucleophiles including ketones, 1,3-dicarbonyl compounds and aldehydes. Electron-rich arenes could be utilized as nucleophiles at elevated temperatures. The reactions are believed to proceed via autoxidation of the benzylic CH bonds to the hydroperoxides and subsequent nucleophilic substitution catalyzed by sulfonic acids

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Nur Sauerstoff und Säure! Die oxidative Kupplung von Xanthen und anderen aktivierten Benzylverbindungen mit Nukleophilen wie Ketonen benötigt lediglich Sauerstoff und katalytische Mengen an Methansulfonsäure. Lösungsmittel sind nicht erforderlich. Der vorgeschlagene Reaktionsmechanismus umfasst die Substrataktivierung durch Bildung eines Hydroperoxids. Daher kann diese Methode als „autoxidative Kupplungsreaktion“ angesehen werden.

n (x) and the generalized Euler polynomials E (α) n (x) of order α and degree n in x. The main purpose of this sequel to some of the aforecited investigations is to give several addition formulas for a general class of Appell sequences. The addition formulas, which are derived in this paper, involve not only the generalized Bernoulli polynomials B (α) n (x) and the generalized Euler polynomials E (α) n (x), but also the generalized Genocchi polynomials G (α) n (x), the Srivastava polynomials S N n (x), several general families of hypergeometric polynomials and such orthogonal polynomials as the Jacobi, Laguerre and Hermite polynomials. Some umbral-calculus generalizations of the addition formulas are also investigated.Mathematics Subject Classification (2010). Primary 11B68; Secondary 11B83, 33C45.

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