The Synthesis Of 6-Trifluoromethyl-Phenanthridines Through Photoreaction

As a unique fluorine-containing group,trifluoromethyl has wide application in pharmaceuticals,agrochemicals and material science due to its small size,strong electron-withdrawing ability and so on.Introducing CF3 to an organic molecular skeleton can change the molecular electronic effect,and the molecular polarity which,thereby,improve the lipophilic,solubility and metabolism of some molecular compounds.Thence,trifluoromethyl-containing compounds play a very important role in the fields of biosciences,high-tech industries,the electronics industry and the defense industry.Phenanthridines and their derivatives are a class of very important structural unit in some natural products and biologically active molecules,Since it has excellent biological activities,potential medicinal value and unique optoelectronic properties,phenanthridines compounds are widely used in many fields,such as pharmaceutical,pesticide,functional materials research.There are lots of methods for the synthesis of phenanthridine derivatives and CF3-containing compounds,however,there are few examples for the synthesis of 6-trifluoromethyl phenanthridines.So,finding facile and high-efficiency strategy to construct such compounds has become one of the important subjects in the field of organic synthesis.As one of the hot spots of green chemistry research in recent years,photocatalysis has been widely used and become an emerging area in organic synthesis.In this dissertation,we investigate the radical tandem cyclization reaction of 2-phenyl isonitrile and trifluoromethanesulfonyl chloride to synthesize 6-trifluoromethyl phenanthridines under the light irradiation without photosensitizer.We obtained the appropriate reaction conditions by screening different parameters.With the the optimized conditions in hand,19 products are formed in 23-89% yields.Such reaction was simple,mild,environmental friendly,and with wide substrate universality,which provided a new way for phenanthridines compounds and was of great significance in the synthesis chemistry.