2734-00-1Relevant academic research and scientific papers
Dehydrogenative α-oxygenation of ethers with an iron catalyst
Gonzalez-De-Castro, Angela,Robertson, Craig M.,Xiao, Jianliang
supporting information, p. 8350 - 8360 (2014/06/24)
Selective α-oxidation of ethers under aerobic conditions is a long-pursued transformation; however, a green and efficient catalytic version of this reaction remains challenging. Herein, we report a new family of iron catalysts capable of promoting chemoselective α-oxidation of a range of ethers with excellent mass balance and high turnover numbers under 1 atm of O2 with no need for any additives. Unlike metalloenzymes and related biomimetics, the catalyst produces H2 as the only byproduct. Mechanistic investigations provide evidence for an unexpected two-step reaction pathway, which involves dehydrogenative incorporation of O2 into the ether to give a peroxobisether intermediate followed by cleavage of the peroxy bond to form two ester molecules, releasing stoichiometric H2 gas in each step. The operational simplicity and environmental friendliness of this methodology affords a useful alternative for performing oxidation, while the unique ability of the catalyst in oxygenating a substrate via dehydrogenation points to a new direction for understanding metalloenzymes and designing new biomimetic catalysts.
Sulfonic acid-catalyzed autoxidative carbon-carbon coupling reaction under elevated partial pressure of oxygen
Pinter, Aron,Klussmann, Martin
supporting information; scheme or table, p. 701 - 711 (2012/04/23)
An aerobic organocatalytic oxidative C-C bond formation reaction of benzylic C-H 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 C-H 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 C-H bonds to the hydroperoxides and subsequent nucleophilic substitution catalyzed by sulfonic acids. Copyright
