Palladium-catalyzed C-H Functionalization Of2-arylbenzothiazoles

C-H bond is one of the most common functional-group among organiccompound.Transition metal-catalyzed C-H bond functionalization is one of the mostefficient, convenient and economic methodologies for the systhsis of targetcompounds based on easily available starting materials with short synthetic routes,which conform to the requirement of modern green synthetic chemistry. Thismethodology opened a new route to form C-C and C-X (X=O, S, N ect.) bonds andattracted much attention of chemists.In chapter one, we summarized the achievements of palladium catalyzed C-Hbond activation which consist of five parts, including the formation of C-C, C-N, C-O,C-S and C-X bonds.Chapters two to four are our research work.In chapter two, we developed Pd(OAc)2catalyzed C-H activation of2-arylbenzothiazoles with aryliodobenzene in TFA. The desired CAr-CArbondformation proceeded efficiently with good functional-group tolerance and highregioselectivity. The substrates bearing electron-donating groups gave better yieldsthan those bearing electron-withdrawing groups.In chapter three a novel Pd-catalyzed regioselective ortho-acyloxylation reactionof2-arylbenzo[d]thiazole is described. A wide substrate scope with good functionalgroup tolerance has been demonstrated, affording mono-ordiacyloxylation productsin moderate to good yields.The substrates bearing electron-donating groups gavebetter yields and regioselectivity than those bearing electron-withdrawing groups.In chapter four we developed two methodologies to acylation methods:1)Pd-Catalyzed ortho-C-H acylation/cross coupling of2-arylbenzo[d]thiazoles withaldehydes;2) Directortho-acylation through an oxidative coupling of2-arylbenzothiazoleswith benzylic alcohols. Substrates bearing electron-withdrawinggroups exhibit good reativities and excellent regioelectivity.