Reactions of trisilylated silylfluorides with potassium tert-butoxide were found to give disilylated fluorosilylenoids. The latter undergo a self-condensation reaction, leading to the formation of beta-fluorodisilanyl anions, which may also be considered as fluoride adducts of disilenes. The stereochemical outcome of this self-condensation depends on the bulkiness of the silyl substituents. Thus, mixtures of diastereomers are obtained in some cases. Reaction of a disilene adduct with magnesium bromide triggers metal fluoride elimination and formation of the respective tetrasilylated disilene. Attempts to exchange one silyl group of the starting material for a methyl, phenyl, or tert-butyl group led to a different course of reaction for the methyl and phenyl cases. The tert-butyl-substituted example gave the expected disilene adduct, but it was not the main product.
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http://dx.doi.org/10.1021/ja805753d | DOI Listing |
Dalton Trans
January 2025
Institut für Anorganische Chemie, University of Stuttgart, Pfaffenwaldring 55, 70550 Stuttgart, Germany.
Angew Chem Int Ed Engl
December 2024
Department of Chemistry and Chemical Biology, Harvard University Cambridge, Massachusetts, 02138, United States.
Sulfenyl fluorides are organic compounds of sulfur in formal oxidation state +2 with the formula R-S-F. Although the chloride, bromide, and iodide analogues have been extensively described in the literature, arenesulfenyl fluorides remain essentially unstudied. These structures have been implicated as putative intermediates in established processes to access polyfluorinated sulfur species; however, definitive and direct evidence of their existence has not been obtained, nor has a systematic understanding of their reactivity.
View Article and Find Full Text PDFThe addition of phosphines (PR) to Michael acceptors is a key step in many Lewis-base catalysed reactions. The kinetics of the reactions of ten phosphines with ethyl acrylate, ethyl allenoate, ethyl propiolate, ethenesulfonyl fluoride, and ethyl 2-butynoate in dichloromethane at 20 °C was followed by photometric and NMR spectroscopic methods. The experimentally determined second-order rate constants show that electronic effects in sterically unencumbered phosphines affect their nucleophilicity towards different classes of Michael acceptors in the same ordering.
View Article and Find Full Text PDFJ Org Chem
October 2024
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany.
The reactions of selected haloacetyl fluorides with the strong Lewis acids AsF and SbF were investigated in the aprotic solvent SOClF. Depending on the stoichiometric ratio of AsF or SbF and the haloacetyl fluorides, either -coordinated adducts or the respective haloacetylium ions were isolated as solids. The compounds were characterized by low-temperature vibrational spectroscopy and single-crystal X-ray diffraction.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
November 2024
Earth System Science Interdisciplinary Center and Department of Geology, University of Maryland, College Park, MD, USA.
Rationale: The analysis of the three sulfur stable isotope ratios (S/S, S/S, S/S) is routinely performed by gas-source isotope ratio mass spectrometry (IRMS) on the SF gaseous molecule, collecting SF ions at m/z ~ 127, 128, 129 and 131. High precision and accuracy are commonly achieved owing to a lack of correction because fluorine has only one isotope and the inert nature of the SF molecule. The analysis of the S/S ratio is, however, complicated by the low abundance of S (~0.
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