Palladium And Copper Catalyzed Unsaturated Ester Transformation Reactions

Palladium-catalyzed tandem cyclization and cross coupling reactions have been developed as one of the straightforward and powerful methods for construction of new C-C and C-O bonds in the pyrone derivatives.Pd(II)-catalyzed one-pot tandem cyclization/alkylation reactions of enynoates with allylic alcohols has been demonstrated.In this reaction,an innovative protocol proceeded well through Pd-catalyzed intramolecular selective 6-endo cyclization,insertion of allylic alcohols into the Pd-C bond of vinylpalladium species generated in situ,and ?-hydrogen elimination processes.This conversion provides a convenient and efficient methodology for the synthesis of 2-alkanone pyrones in moderate to good yields.A copper-catalyzed regioselective synthetic method was well-established for 1,4-and 1,6-conjugate additions of silyl reagent to the diendioates.Various 1,4-and 1,6-protosilylation adducts were obtained in good yields with high regioselectivity by tuning the ligand under mild reaction conditions.This dominant and effective methodology emerged for the synthesis of multisubstituted 1,4-and 1,6-protosilylation adducts.In this work we mainly focus on the control of regioselectivity.This thesis mainly includes the following two parts:The first chapter describes the introduction,applications and synthetic methods of pyrone derivatives.This chapter mainly focus on the Palladium-catalyzed one-pot highly regioselective 6-endo cyclization and alkylation of enynoates to synthesize of 2-alkanone Pyrones.The second chapter deals the introduction of C-Si bond formation,applications of organosilicon compounds,and examples of regioselective 1,4-and 1,6-conjugate additions of silyl reagent.We have devolped a regiodivergent copper-catalyzed 1,4 and 1,6-conjugate additions of silyl reagent to the diendioates.