1085703-82-7Relevant academic research and scientific papers
Insights into the mechanism of the ruthenium-porphyrin-catalysed allylic amination of olefins by aryl azides
Intrieri, Daniela,Caselli, Alessandro,Ragaini, Fabio,MacChi, Piero,Casati, Nicola,Gallo, Emma
experimental part, p. 569 - 580 (2012/03/12)
This paper describes the synthesis of allylic amines by aryl azides (ArN3) catalysed by [Ru(TPP)CO] (TPP = dianion of tetraphenylporphyrin). The employment of aryl azides renders the methodology sustainable as the formation of molecular nitrogen is the only stoichiometric byproduct. The isolation of catalytic intermediates and spectroscopic and kinetic studies revealed interesting information about the reaction mechanism, which could improve its catalytic efficiency in future research. An important result is the X-ray characterisation of [Ru(TPP)(ArN)2] [Ar = 3,5-(CF3)2C6H3], which is active in both stoichiometric and catalytic nitrene transfer reactions. The proposed involvement of carbonyl-monoimido-ruthenium porphyrin complexes in the catalytic cycle is also derived from our kinetic and experimental results. All the data indicate the coexistence of two mechanisms, where the electronic nature of the engaged aryl azide and olefin concentration determine one mechanism or the other. Copyright
Calcium-catalyzed direct amination of π-activated alcohols
Haubenreisser, Stefan,Niggemann, Meike
supporting information; experimental part, p. 469 - 474 (2011/04/16)
A calcium-catalyzed direct amination of π-activated alcohols with different nitrogen nucleophiles under very mild reaction conditions is presented. The high reactivity of the calcium catalyst allows for an efficient conversion of secondary and tertiary benzylic and allylic as well as tertiary propargylic alcohols. Nitrogen nucleophiles such as carbamates, tosylamides and anilines are readily alkylated at room temperature.
Allylic amination and aziridination of olefins by aryl azides catalyzed by CoII(tpp): A synthetic and mechanistic study
Caselli, Alessandro,Gallo, Emma,Fantauzzi, Simone,Morlacchi, Simona,Ragaini, Fabio,Cenini, Sergio
experimental part, p. 3009 - 3019 (2009/03/11)
CoII(tpp) catalyzes the reaction of aromatic azides (ArN 3) with nonactivated olefins to yield allylic amines or aziridines in moderate-to-good yields. The chemoselectivity of the catalytic reaction is particularly high. Depending on the substrate employed, allylic amines or aziridines can be obtained. The reaction mechanism was investigated, and the reaction proceeds through reversible coordination of the aryl azide to the CoII-porphyrin complex. The often postulated nitrene complex is not an intermediate in this reaction. The kinetics for the allylic amination is first order in azide, Co(tpp), and olefin. For the aziridination, the kinetics is again first order in azide and catalyst, but we observed a first-order dependence of the rate on α-methylstyrene only up to an olefin concentration of 6.9 M. An inhibiting role of the competitively formed 1-(4-nitrophenyl)-5-methyl-5-phenyl-1,2,3-triazoline was identified. The triazoline was shown to reversibly coordinate to Co(tpp), which blocks the free coordination site necessary for the catalytic reaction to proceed, and is it responsible for the catalyst deactivation in the aziridination reaction of α-methylstyrene by 4-nitrophenyl azide. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
