Brønsted acidic ionic liquid accelerated halogenation of organic compounds with N-halosuccinimides (NXS)
The Brønsted-Acidic ionic liquid 1-methyl-3-(4-sulfobutyl) imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into a-halo and a,a-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of a-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions. © 2013 by the authors.
Digital Object Identifier (DOI)
Vražič, Jereb, M., Laali, K. K., & Stavber, S. (2012). Brønsted acidic ionic liquid accelerated halogenation of organic compounds with N-Halosuccinimides (NXS). Molecules, 18(1), 74–96. https://doi.org/10.3390/molecules18010074