Alkene cis-Dihydroxylation by [(Me3tacn)(CF3CO2)RuVIO2]ClO4 (Me3tacn = 1,4,7-Trimethyl-1,4,7-triazacyclononane): Structural Characterization of [3 + 2] Cycloadducts and Kinetic Studies
| Autor: | Chi-Ming Che, Nianyong Zhu, Wing Ping Yip, Wing-Yiu Yu |
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| Rok vydání: | 2005 |
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| Zdroj: | Journal of the American Chemical Society. 127:14239-14249 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja0528230 |
| Popis: | cis-Dioxoruthenium(VI) complex [(Me3tacn)(CF3CO2)RuVIO2]ClO4 (1, Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane) reacted with alkenes in aqueous tert-butyl alcohol to afford cis-1,2-diols in excellent yields under ambient conditions. When the reactions of 1 with alkenes were conducted in acetonitrile, oxidative CC cleavage reaction prevailed giving carbonyl products in >90% yields without any cis-diol formation. The alkene cis-dihydroxylation and CC cleavage reactions proceed via the formation of a [3 + 2] cycloadduct between 1 and alkenes, analogous to the related reactions with alkynes [Che et al. J. Am. Chem. Soc. 2000, 122, 11380]. With cyclooctene and trans-β-methylstyrene as substrates, the Ru(III) cycloadducts (4a) and (4b) were isolated and structurally characterized by X-ray crystal analyses. The kinetics of the reactions of 1 with a series of p-substituted styrenes has been studied in acetonitrile by stopped-flow spectrophotometry. The second-order rate constants varied by 14-fold despite an ... |
| Databáze: | OpenAIRE |
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