Department of Basic and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, via Castro Laurenziano, 7, 00161 Rome, Italy.
Department of Chemistry, Sapienza University of Rome, piazzale Aldo Moro, 5, 00185 Rome, Italy.
J Org Chem. 2021 Nov 19;86(22):16151-16157. doi: 10.1021/acs.joc.1c00932. Epub 2021 Jul 2.
The anodic oxidation of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF) efficiently generates BF from BF. This Lewis acid, strongly bound to the ionic liquids, can be efficiently used in classical BF-catalyzed reactions. We demonstrated the BF/BMIm-BF reactivity in four reactions, namely, a domino Friedel-Crafts/lactonization of phenols, the Povarov reaction, the Friedel-Crafts benzylation of anisole, and the multicomponent synthesis of tetrahydro-11-benzo[]xanthen-11-ones. In comparison with literature data using BF-EtO in organic solvents, in all the presented cases, analogous or improved results were obtained. Moreover, the noteworthy advantages of the developed method are the generation of BF (no storing necessity) in the required amount, using only the electron as redox reagent, and the recycling of BMIm-BF for multiple subsequent runs.
1-丁基-3-甲基咪唑四氟硼酸盐（BMIm-BF）的阳极氧化可有效地将 BF 转化为 BF。这种与离子液体结合紧密的路易斯酸可有效地用于经典的 BF 催化反应中。我们在四个反应中展示了 BF/BMIm-BF 的反应性，分别为酚的串联 Friedel-Crafts/内酯化、Povarov 反应、苯甲醚的 Friedel-Crafts 苄基化以及四氢-11-苯并[]氧杂蒽-11-酮的多组分合成。与使用 BF-EtO 在有机溶剂中的文献数据相比，在所有呈现的情况下，都获得了类似或改进的结果。此外，该方法的显著优点是仅使用电子作为氧化还原试剂，以所需量生成 BF（无需储存），并可多次回收 BMIm-BF 用于后续反应。
