Tetrahedron Letters ( IF 1.5 ) Pub Date : 2018-01-13 , DOI: 10.1016/j.tetlet.2018.01.026 Guangchang Liu , Bo Xu
We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
中文翻译:
氢键供体溶剂可实现无金属和无卤素的Friedel-Crafts酰化反应,几乎没有废物流
我们已经开发了一种无金属,无卤素的Friedel-Crafts酰化方案,几乎没有废物流产生。我们建议氢键供体溶剂将形成氢键网络,并可能显着提高Friedel-Crafts反应的速率。三氟乙酸是最强的氢键供体溶剂之一,它也是易挥发的,可以通过蒸馏容易地回收而无需进行反应后处理。我们的方案是“绿色”的Friedel-Crafts酰化工艺:1)催化剂可以回收再利用;2)使用无卤素的起始原料(羧酸酐或羧酸);3)无需进行水相反应后处理;4)最少或没有废蒸汽产生。