Aryloxylation Reaction Of Gem-difluoroalkenes With Arylboronic Acids

The introduction of a fluorine atom or fluorine-containing group into organic molecules can improve the physicochemical characteristics and biological activities of small organic molecules, and therefore, the design and synthesis of fluorine-containing compounds are attracted increasingly attention. Fluorovinyl ether structure is a novel fluorine-containing building block with excellent reaction properties, and it has been widely applied in the areas of material chemistry, pharmaceuticals and pesticides. In this thesis, we focused on gem-difluoroalkenes and developed a method for the synthesis of fluorovinyl aryl ethers by a three component reaction of gem-difluoroalkenes with arylheteroboronic acids or pyridine-4-ylboronic acid and oxygen. Thirty-two novel products were synthesized and all of these have been confirmed by 1H NMR、13C NMR、19F NMR and HRMS.1. In this chapter, we studied the aryloxylation reaction of gem-difluoroalkenes, using symmetrical 1,1-diaryl-2,2-difluoroethylene, aromatic boric acid and oxygen as the substrates. By the optimization of reaction conditions, we ultimately determined to use 2.0 eq K3PO4 as base, NMP as solvent, at the condition of 100 ℃,24 h under air atmosphere. At the same time, the aryloxylation reaction of asymmetric fluoroalkenes was studied. Unfortunately, the products were E/Z mixture with poor stereoseectivity. Twenty-one novel fluorovinyl aryl ethers compounds were synthesized.2. E-selectivity connfiguration fluorovinyl pyridyl ethers were synthesized by the aryloxylation reaction of 1-aryl-2,2-difluoroethenes with pyridine-4-ylboronic acid under the optimized reaction condition. The coupling constants of 1H NMR、19F NMR showed that Z isomer is not occured. In this chapter, we synthesized eleven novel E-type fluorovinyl pyridyl ethers compounds.