Abstract
Eight substituted aryl(indol-3-yl)methylium tetrafluoroborates 3(a-h)-BF4 and three bis(indol-3-yl)methylium tetrafluoroborates 3(i-k)-BF4 have been synthesized and characterized by NMR spectroscopy and X-ray crystallography. Their reactions with π-nucleophiles 8(a-j) (silylated enol ethers and ketene acetals) were studied kinetically using photometric monitoring at 20 °C. The resulting second-order rate constants were found to follow the correlation log k(20 °C) = sN(N + E), in which nucleophiles are characterized by the two solvent-dependent parameters N and sN, and electrophiles are characterized by one parameter, E. From the previously reported N and sN parameters of the employed nucleophiles and the measured rate constants, the electrophilicities of the indol-3-ylmethylium ions 3(a-k) were derived and used to predict potential nucleophilic reaction partners. A discrepancy between published rate constants for the reactions of morpholine and piperidine with the (2-methylindol-3-yl)phenylmethylium ion 3h and those calculated from E, N, and sN was analyzed and demonstrated to be due to a mistake of the value reported in the literature.
Original language | English |
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Pages (from-to) | 8643-8656 |
Number of pages | 14 |
Journal | Journal of Organic Chemistry |
Volume | 80 |
Issue number | 17 |
DOIs | |
Publication status | Published - 28 Jul 2015 |
Externally published | Yes |
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CCDC 996887: Experimental Crystal Structure Determination
Berionni, G. (Contributor), Follet, E. (Contributor), Mayer, P. (Contributor) & Mayr, H. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2015
DOI: 10.5517/cc12gbnj, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc12gbnj&sid=DataCite
Dataset
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CCDC 996885: Experimental Crystal Structure Determination
Berionni, G. (Contributor), Follet, E. (Contributor), Mayer, P. (Contributor) & Mayr, H. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2015
DOI: 10.5517/cc12gblg, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc12gblg&sid=DataCite
Dataset
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CCDC 1011256: Experimental Crystal Structure Determination
Berionni, G. (Contributor), Follet, E. (Contributor), Mayer, P. (Contributor) & Mayr, H. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2015
DOI: 10.5517/cc12y95h, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc12y95h&sid=DataCite
Dataset