Study Of Synthesis Of Nitriles From Carboxylic Acids And Decarboxylation Allylation Based On Metal/Photocatalyst Participation

The construction of carbon-carbon bonds and carbon-hetero bonds has been a lot of topic in organic synthesis.Transformations and decarboxylative couplings of carboxylic acids have emerged as a powerful tool to achieve the formation of new chemical bonds,along with the extrusion of CO2 and ipso-functionalizations.Moreover,carboxylic acids are ideal substrates because they are widely available and easy to store and handle.In recent years,a large number of catalytic conversions from carboxylic acid have been developed,providing various valuable products.However,most of the traditional transition metal-catalyzed decarboxylative couplings rely onexpensive metal catalysts.Herein,cheap iron salts were used as the catalyst to realize the direct synthesis of nitriles from carboxylic acids.The decarboxylative allylation of silanecarboxylic acids has been also achieved enabled by visible light catalysis system,which opens up new methods for the development of decarboxylation.1.Iron-catalyzed direct conversion of carboxylic acids to nitrilesThe conversion of carboxylic acids to nitriles is an important method for synthesizing nitrile compounds,but established methods have many drawbacks,such as the requirement of high temperatures(>200℃),expensive transition metal catalysis,and cumbersome steps.In this paper,we developed a straightforward access to nitriles in moderate to high yields from ubiquitous carboxylic acids,using electron-deficient N-cyano-N-aryl-arylsulfonamide(NCAS)underl inexpensive iron-catalyzed system.The reaction is tolerant to a wide range of functional groups and is generally compatible with primary,secondary,tertiary,and aryl carboxylic acids.A total of 36 substrates were demonstrated.2.Photo/nickel cooperatively catalyzed decarboxylation of silanecarboxylic acidsCompared to the reported silyl radical precursors,silanecarboxylic acids exhibit advantages,such as high-stability.Herein,we use silanecarboxylic acids as a silyl radical precursor to achieve their decarboxylative allylation with allyl acetates under a photo and nickel dual catalytic system,providing a concise and efficient approach to the synthesis of allylsilanes.A total of 44 substrates were developed,and various allylsilanes products were obtained with good to excellent yields.Through the calculation and mechanism exploration experiment of density functional theory(DFT),we proposed the mechanism of the reaction:silyl radicals were produced from silanecarboxylic acids under visible light irradiation,along with the extrusion of CO2,while nickel catalyzed the oxidative addition of allyl acetates,followed by radical addition to finish the final products Among them,the regioselectivity of the reaction is controlled by the attack of silyl radicals to terminal allyl carbon atoms with less steric hindrance.3.Photoredox catalyzed direct decarboxylative allylation of silanecarboxylic acidsEstablished methods for the synthesis of allylsilanes often required transition metal catalysts.In this part,2-(p-toluenesulfonylmethyl)acrylates were utilized as the allyl sources,with the assist of organic photocatalysts,decarboxylative allylation of silanecarboxylic acids could be readily realized,synthesizing a variety of allylsilane compounds with high efficiency.This reaction not only featured the advantages such as mild conditions,but also does not require additional transition metal catalysts and oxidants,opening up a green entry for the synthesis of allylsilanes.