Studies On The Copper-catalyzed C-S Coupling Reactions And Tandem Reactions Initiated By C-C Coupling

The copper-catalyzed C-C and C-heteroatom coupling transformations are one of the major classes of methodologies in the construction of C-C and C-heteroatom bonds. These couplings have already exhibited irreplaceable application in organic synthesis such as natural product synthesis, pharmaceuticals and materials. Therefore,the researches on the copper-catalyzed coupling reactions as well as related application are of high significance. This thesis reports our work in the field of copper-catalyzed C-S coupling and tandem reactions based on the C-C coupling. Four sections of research work are included in the thesis.(1) Copper-catalyzed selective single C-S coupling reactions of dihalobenzenes.By using dihalobenzenes and thiophenols as starting materials, we successfully realized the copper-catalyzed the selective sulfenylation of a single Ar-I bond of the dihalobenzenes. A class of sulfides containing iodoaryl fragement have been readily synthesized via this method, and these products paved the way for synthesizing more complex sulfur-containing products via further Ar-I bond elaboration.(2) Copper-catalyzed selective bis-C-S coupling reactions of dihalobenzenes.Based on systematical exploration, we achieved the selective bis-sulfenylation on the two Ar-halo bonds of dihalobenzenes by employing disulfides as thiolating reagents under the condition of copper catalysis. This method allowed the smooth synthesis of aryl bisthioesters by one step, and both aryl as well as alkyl disulfides displayed tolerance to the synthetic protocol.(3) Copper-catalyzed one-pot synthesis of benzofurans using phosphorus ylides,acyl chlorides and o-iodophenols. Based on the precursors of phosphorus ylides and acyl chlorides, the in situ generated allenes underwent tandem transformations of Michael addition and C-C coupling etc in the presence of o-iodophenols. This approach avoided the isolation of sensitive allene and provided concise synthesis of target products via the formation of a C(sp2)-C bond, a C(sp2)-O bond and a C=C double bond.(4) The dichloromethane carbon source-based tandem synthesis of 2-vinyl benzofurans. On the basis of the above on pot synthesis of benzofurans, further modification on the operation and reaction conditions led to the establishment of2-vinyl benzofuran synthesis starting from phosphorus ylides, acyl chlorides,o-iodophenols and dichloromethane. This method was based on the key functionalization of p3C-H andsp3C-Cl bonds, which also represented the first synthetic method allowing direct synthesis of 2-vinyl benzofurans.