Studies On Construction Of The C-F Bond And C-F₂ Bond In α,β-dicarbonyl Compounds Under Mechanical Ball Milling Conditions

Organic fluorine compounds have special physical and chemical properties, which make great concern on the study of constructing C-F bond to organic compounds. The break-through of several construction methods, such as new fluoride reagent and fluoride slab method, promotes the development of fluorinated drugs. At present, fluoridation needs a mass of fluoride reagents and organic solvents. Especially, both lots of energy and time are needed during the production in the factory. The separation of the fluoride product is very difficult, which leads to high cost in the preparation. Such conditions immensely limit the application of fluoride. Thus, it is imperative to explore new methods and techniques in fluorination with the concepts of green chemistry. In the different ways of green synthesis, mechanical ball milling has been developing rapidly in the recent years. And it has great application prospects in industrial production. The method makes the reaction occur under the great effect of mechanical energy which is generated by milling pots impaction. Notably, the process is generally carried out in solvent-free conditions, and the reaction occurs quickly with high efficiency. In addition, it is easy to grasp and deal with. So the method is highly consistent with the concept of "Green Chemistry". This paper aims to the advantages of mechanochemical method on the construction of C-F bond and C-F2 bond to α,β-dicarbonyl compounds under mechanical ball milling conditions, and works on the exploration of the following aspects:The construction of C-F bond through the reaction of 1,3-dicarbonyl compounds with industrialized selectfluor under ball-milling conditions. This reaction is conducted at a frequency of 20 Hz, and it takes 10 min to obtain the target products in the best yield of 94% with the present of solvent-free. The method provides a new route of fluorination for fluorine chemical researchers. The work also went on a set of reactions under the magnitude of gram scale and achieved good results ultimately, which means that the method has great prospect in the industrial development in the future.The construction of C-F2 bond through the reaction of acetoacetamides with industrialized selectfluor under ball-milling conditions. This reaction is conducted at a frequency of 20 Hz, and it takes 30 min to obtain the target products in the best yield of 90% with the present of solvent-free and base-free. The method has wide use in various areas. It also possesses easy operation, quick reaction and high yield, which has great practical significance to achieve the "Green Chemistry" concept.