Light-Induced Decarboxylation And Oxidative Formylation Reactions

Decarboxylation and oxidative acylation are effective methods for the synthesis of methyl ketone pesticides(pharmaceutical)intermediates and amide biomacromolecule skeletons.The free radicals were transferred from single electron transfer(SET)in visible-light-induced organic synthesis reaction,which followed by coupling of other species for formation of target molecules,and have appealed extensive attentions and become a powerful strategy owing to its prominent advantages in step-and-atom efficiency in last decade.Rose bengal,eosin Y,Ru(bpy)3Cl2 and Ir(ppy)3 have proven to be efficient photocatalysts for decarboxylation and oxidative acylation reactions.In the absence of photo-sensitizer participation,hypervalent iodine reagents can catalyze the decarboxylation cross-coupling reaction of ?-oxocarboxylic acids under the visible-light induced conditions.Based on the research work above,the main work of this thesis is as follows :(1)A visible-light induced decarboxylative acylarylation of phenyl propiolates with?-oxocarboxylic acids was developed.In the presence of a hypervalent iodine reagent(BI-OH)as catalyst,the reactions generated the corresponding coumarin derivatives in good yields at room temperature under blue LED(450–455 nm)irradiationconditions without photoredox catalyst.The reaction conditions are mild?simple and effective,and the decarboxylation acylation reaction of ?-oxocarboxylic acids induced by visible light.The reaction system has a wide range of substrates,and 3-acyl substituted coumarin compounds were obtained in good yields.?-oxocarboxylic acids,which has different steric(ortho-position,meta-position,para-position)and electronic effect(rich and lack of electrons)substituent groups,could be carry out decarboxylation acylation cyclization reaction.(2)A photoinduced oxidative formylation of N,N-dimethylanilines with molecular oxygen in the absence of external photocatalyst was developed,providing thecorresponding formamides in good yields under mild reaction conditions.Investigations indicated that both starting material and product act as photosensitizers and 1O2 is coexisting with O2·-during the reaction through energy transfer and single electron transfer process.N-methyl(N-alkyl)aniline was irradiated by(380–385 nm)light in DME conditions,oxygen could be selectively oxidized C(sp3)–H bond to build amide derivatives.The broad spectrum of this reaction substrate is good,N-methyl(N-alkyl)secondary amine and tertiary amine are well adapted to this reaction system.Fortunately,Alkenyl(1,3,3-trimethyl-2-methyleneindoline),diphenylmethane and diphenylmethanol can be oxidized to form the carbonyl compounds.