Fe(PyTACN)‐Catalyzed cis‐Dihydroxylation of Olefins with Hydrogen Peroxide. Issue 5 (15th March 2013)

• Record Type: Journal Article
• Authors: Prat, Irene; Font, David; Company, Anna; Junge, Kathrin; Ribas, Xavi; Beller, Matthias; Costas, Miquel
• Is Part Of: Advanced synthesis & catalysis. Volume 355:Issue 5(2013)
• Page Start: 947
• Page End: 956
• Publication Date: 2013-03-15
• Subjects: Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201200938
• Languages: English
• ISSNs: 1615-4150

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A family of iron complexes with general formula [Fe(II)(<sup>R, Y, X</sup>PyTACN)(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>], where <sup>R, Y, X</sup>PyTACN=1‐[2′‐(4‐Y‐6‐X‐pyridyl)methyl]‐4, 7‐dialkyl‐1, 4, 7‐triazacyclononane, X and Y refer to the groups at positions 4 and 6 of the pyridine, respectively, and R refers to the alkyl substitution at N‐4 and N‐7 of the triazacyclononane ring, are shown to be catalysts for efficient and selective alkene oxidation (epoxidation and <italic>cis</italic>‐dihydroxylation) employing hydrogen peroxide as oxidant. Complex [Fe(II)(<sup>Me, Me, H</sup>PyTACN)(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>] (<bold>7</bold>), was identified as the most efficient and selective <italic>cis</italic>‐dihydroxylation catalyst among the family. The high activity of <bold>7</bold> allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and under conditions where the olefin is not used in large amounts but instead is the limiting reagent. In the presence of 3 mol% of <bold>7</bold>, 2 equiv. of H<sub>2</sub>O<sub>2</sub> as oxidant and 15 equiv. of water, in acetonitrile solution, alkenes are <italic>cis</italic>‐dihydroxylated reaching yields that might be interesting for synthetic purposes. Competition experiments show that <bold>7</bold> exhibits preferential selectivity towards the oxidation of <italic>cis</italic> olefins over the <italic>trans</italic> analogues, and also affords better yields and high [<italic>syn</italic>‐diol]/[epoxide] ratios when <italic>cis</italic> olefins are oxidized. For aliphatic substrates, reaction yields attained with the present system compare favourably with state of the art Fe‐catalyzed <italic>cis</italic>‐dihydroxylation systems, and it can be regarded as an attractive complement to the iron and manganese systems described recently and which show optimum activity against electron‐deficient and aromatic olefins.</p> </abstract>