Study On Palladium/Copper-Catalyzed Sonogashira Reaction And Base Promoted C-C, C-N Coupling Reaction

The palladium complexes catalyzed cross-coupling of aryl-halides orhalogenated olefins with terminal alkynes is named Sonogashira reaction, which is aeffective method to obtain a serious of compounds such as aryl alkyne, enynes andacetylenic ketone. In the catalytic system, the catalyst is the complexes that formed bycommonly used palladium and copper(I) with ligands, and that is relativelycomplicated and relatively expensive. Based on the screening of already existedtransitional-metal catalyzed system and optimation of the reaction system, weestablished a newly catalytic system in the dissertation, which is of better applicabilityand yield with the Sonogashira reaction of substrates such as aryl-halides andheterocyclic aromatics. At the same time, the metal-free Sonogashira reaction as well asthe C-C, C-N coupling reaction was also explored and studied. The structures of theproducts in the experiment are characterized by1H NMR,13C NMR and IR.This paper is divided into three main parts:The first part is a in-depth review of the Sonogashira reaction. Firstly, a briefintroduction of the background and the reaction mechanism is given; secondly, aliterature review on the types and catalytic conditions of the Sonogashira reaction isdescribed. Finally, the applications of the Sonogashira reaction in the synthesis oforganic polymer is introduced.The second part is about the alkynylation catalyzed by a catalytic system ofCuI/Pd(OAc)2/PPh3. CuI/Pd(OAc)2/PPh3catalyzed Sonogashira reactions ofarylhalides with phenylacetylene have been observed and discussed. The resultsshowed the advantages like high-yielding, large scope of substrates of the developedcatalytic system by the observed promising results from the reactions of aryl-idiodes, bromides and chlorides. Under the optimized conditions, the Sonogashira reactions ofiodobenzene with phenylacetylene carried out smoothly to provide the correspondingcoupling products in98%yield, while the reactions of aryl-bromides andaryl-chlorides with phenylacetylene can also produce products but in moderate togood yields. Noteworthy is that this low-cost effective and environmentally friendlyprotocol was the first to be employed in Sonogashira reaction. It’s catalytic Sonogashiracoupling reaction of iodobenzene with phenylacetylene yield up to98%. The catalystsystem catalyzed aryl bromides, heterocyclic aromatics and phenylacetyleneSonogashira coupling reaction can be above the average reaction yield. Compared withthe traditional Sonogashira catalytic system, CuI/Pd(OAc)2/PPh3catalytic system hassome outstanding advantages:(1) the system is simple and easy to perform;(2) thereagents of the system are cheap and readily accessable;(3) and the reactionconditions are mild and facile to control.In the third part we take the KOH/DMSO system into the Sonogashira couplingreaction of iodo-aromatics and phenylacetylene without the presences of metalcatalysts and ligands for the first time, and successfully achieved the Sonogashiracoupling products. With advantages of metal catalysts-free and ligands-free, low cost,environmentally friendly and simple operation, the system could be applied to theSonogashira coupling reaction of aryl-iodoides with phenylacetylene, whilearyl-bromides and aryl-chlorides were not found to yield any desired products. Thephenomena showed the inadequacies of applicability of the substrate, and werehypothesized to result from the high activity of aryl-iodoides and the poor reactivatesof aryl-bromides and aryl-chlorides. Further applications of the KOH/DMSO systemwere applied to C-C and C-N coupling reactions, and the implementation of the C-Ncoupling reaction of aryl sulfonamides with iodobenzene and the C-C coupling reactionof iodobenzene with dicyanomethane guaranteed a successfully obtaination the targetproducts. Our study demonstrates that the metal-free and ligands-free reaction systemcan be applied to the C-C and C-N coupling reaction of aryl-iodoides with activehydrogen contained compounds, and the stronger the leaveation of active hydrogen, thehigher of the reaction yield.