Transition Metal Catalyzed Decarboxylative Cross-Coupling Reaction Of ?,?-Unsaturated Carboxylic Acids

In recent decades,transition-metal catalyzed decarboxylative cross-coupling reaction of ?,?-unsaturated carboxylic acid has attracted considerable interests in organic chemistry due to its high efficiency on the formation of carbon-carbon and carbon-heteroatom bonds.Compared to classical transition-metal catalyzed cross-coupling reactions using alkenes and alkynes as substrates,this strategy has the advantages of high chemoselectivity,broad substrate scope and green reaction conditions.In this thesis,cinnamic acids and arylpropiolic acids were applied as substrates to react with different reaction partners to form disubstituted alkenes and alkynes via transition-metal catalyzed decarboxylative cross-coupling reactions.The first chapter is the summary of the works on the decarboxylative cross-coupling reactions of cinnamic acids and arylpropiolic acids published in recent years.In addition,the main content and architecture of this thesis is also described.In the second chapter,an iron-catalyzed decarboxylative methylation reaction was developed.In this reaction,di-tert-butyl peroxide acts as methylation reagent as well as oxidant.Various substituted cinnamic acids were tested and afforded the desired products in moderate yields.In the third chapter,we developed efficient methods for the synthesis of vinyl sulfones through the decarboxylative cross-coupling reaction of arylpropiolic acids with sulfonyl reagents.A copper catalyst was required when arylsulfonyl hydrazides was applied as sulfonyl reagent.Catalytic amount of ferrous chloride and 3 equivalent of di-tert-butyl peroxide favored the reaction and promoted the yield dramatically.When sodium sulfinate was chosen as sulfonyl reagent,the reaction can proceed without catalyst,but phosphoric acid was required as proton source.A plausible non-radical mechanism was proposed based on the results of control experiments.In the chapter 4,we realized the copper-catalyzed cyanation of terminal alkynes uising azodiisobutyronitrile as cyanation reagents.Various terminal alkynes were tolerated and afforded the corresponding products in moderated to good yields.Interestingly,vinyl isobutyronitrile was selectively generated when the reaction proceeded under argon atmosphere.A feasible mechanism was proposed based on the results of control experiments.In the chapter 5,we further developed the application of azodiisobutyronitrile.It was found that azodiisobutyronitrile can be served as an effective amination reagent to react with carboxylic acids to form tertiary or secondary amides.A series experiments were conducted to explore the mechanism.We found that the secondary amide was generated through the hydrolysis of the corresponding tertiary amides.