Catalytic Amounts Of DDQ-promored Cross-dehydrogenative Coupling Reaction

Carbon-carbon bond-forming and carbon-heteroatom bond-forming reactions through oxidative cross-dehyrogenative coupling(CDC)reactions have been in the limelight recently,mainly because CDC methods do not require pre-functionalized precursors prior to the coupling reactions,and are atom economical and environmentally benign.DDQ,as an effective oxidant,is widely used in these coupling reactions.However it is always employed in a stoichiometric amount or more led to purification difficulties of the resultingby-product DDQH2.From the view of the cost concern and atom economy,it needs to search for economical and environmentally benign co-oxidants to regenerate DDQ.This dissertation mainly focuses on the study of the CDC reactions catalyzed by DDQ,using dioxygen as a co-oxidant with suitable additives.Our work mainly includes two parts.Part one:Taking DDQ/AIBN/02 catalytic system to form the CDC reaction of 1,3-diarylpropenes with active metwhich hylenic compounds,oximes,alcohols,anilines and amides.Using 20 mol%AIBN as an additive to activate molecular oxygen to regenerate DDQ,the coupling products were obtained in moderate-good yields.The amounts of DDQ were reduced to 20 mol%.Part two:Taking DDQ/NaNO2/O2 catalytic system to form the CDC reaction of 1,3-diarylpropenes with active methylenic compounds.NO released from NaNO2 in the presence of HCOOH was oxidized to NO2 by dioxygen.The by-product DDQH2 was oxidized to regenerate DDQ by in-situ NO2.The reaction was carried out for half an hour at 40? and the coupling products can be obtained with high yields.The amounts of DDQ were reduced to 1 mol%.This catalytic system can also be applied in the coupling reaction between 1,3-diarylpropynes and active methylenic compounds.We have developed the two oxidative systems to regenerate DDQ by adding suitable additives,using molecular oxygen as the co-oxidant.The amounts of DDQ were reduced to 1 mol%.Both two catalytic systems also provide a concise and efficient method for the synthesis of the corresponding compounds.