Study On Synthesis Of Benzophenone Derivatives And Sp~2C-H Bond Activation

Aryl ketones are common structural motifs in functional molecules and natural products,and are important precursors formany elaborate organic compounds. The traditional synthesis of aryl ketones employs Friedel-Crafts acylation of aromatic compounds,There are some drawbacks with this reaction, such as hash reaction conditions, untunable regiocontrol, low substrate scope, and releasing large amounts of waste. Recently, palladium-catalyzed cross-coupling of boronic acids with carboxylic derivatives has been developed as a powerful protocol to synthesize regioselectively aromatic ketones,Such approach is superior to the previous methods in terms of mildness of reaction conditions, selectivity, and efficiency.However there are some challenges,which still exist for this process, such as high catalyst loading and limited substrate scope. Therefore, it is great interest to explore highly efficient catalytic systems. In the first part of this paper, Our have synthesized aromatic ketones with potassium aryltrifluoroborates catalyzed by Rh catalyst with a new and convenient way. Potassium aryltrifluoroborates was used to synthesize aromatic ketones due to its character of stable, nontoxic, easily-prepared. This newly catalyst system of RhCl(PPh3)3/CuI is environmentally friendly, cost savings and applicable to a wide range of carboxylic anhydrides and affords yields of up to95%. This reaction overcome inert atmosphere conditions and low yield. RhCl(PPh3)3exhibited highly catalytic activity for the cross-coupling reaction between potassium aryltrifluoroborates and carboxylic anhydrides with low catalyst loading (1mol%). The reactions went smoothly in xylene phase to give good yields of aryl ketones in short reaction times and unaffected by the presence of electron-releasing and electron withdrawing substituents in both the potassium aryltrifluoroborates and carboxylic derivatives. However, the yield is affected due to their steric constraints.In the second part of this paper, According to one of the most popular strategies is the use of a chelate-assistant which uses the aid of a neighboring directing group that precomplexes the metal and directs it to the desired position.In this system, Pd(OAc)2was used as the catalyst, TBHP as an oxidant,The catalytic system was applied to the direct oxidative coupling of2-phenylpyridine with chelate-assistant and mandelic acid derivatives.The TBHP as an oxidative which was demonstrated to be an essential component in this reaction.The catalytic system was applied to the direct oxidative coupling of a series of2-phenylpyridine and mandelic acid derivatives.,and the corresponding products with special chemo-and regio-selectiveity were afforded in high yields.This reaction provides an atom novel and efficient route to phenyl-(2-(pyridin-2-yl)phenyl)methanone derivatives which are widely used in various fine chemicals.