Brønsted Acidic Ionic Liquid Accelerated Halogenation of Organic Compounds with N-Halosuccinimides (NXS)

Molecules

Dejan Vražič¹  Marjan Jereb¹  Kenneth K. Laali¹ 

[1] ¹Laboratory for Organic and Bioorganic Chemistry, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia

关键词: Brønsted-acidic ionic liquid;    halogenation;    aromatic ketones;    NXS reagents;    green chemistry;   

DOI  :  10.3390/molecules18010074

来源: mdpi

【 摘 要 】

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 α-halo and α,α-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of α-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.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.