Construction Of 2,3-Dihydrobenzofuran Skeleton Catalyzed By Cu/SPDO And Synthesis Of Iridium Complexes With Spirocyclic NHC Framework

In recent years,the field of asymmetric catalysis involving metal Lewis acids has been developed rapidly,in this topic the development of new chiral catalysts and the exploration of new catalytic model have been received all kinds of attetions.However,the construction of complicated chiral skeleton in most cases is started from simple chiral precursors compounds through multi-step transformation,and research on the efficient synthesis of key structure by using catalytic asymmetric reactions are rarely reported.The chiral 2,3-dihydrobenzofuran skeleton exists in many natural products,such as(+)-Decursivine,(+)-Lithospermic acid,(-)-Rocaglamide,Corsifuran A-B and so on.However,due to the hindrance effects of quaternary carbon stereo center,the enantioselective control is more difficult.Consequently,the synthesis of bioactive molecules with quaternary carbon centers and polycyclic structures remains challenging.Therefore,the development of asymmetric synthesis methods for such skeletons is of great necessity.Meanwhile,since the exploration of the chemistry of transition metal carbene complexes in 1964,the research on N-heterocyclic carbene(NHC)metal complexes has always been one of the cutting-edge fields in organometallic chemistry,and it has been widely applied in many organic reactions.Therefore,designing and synthesizing a novel N-heterocyclic carbene metal complex is of necessity in the field of the organometallic chemistry.This thesis consists of three chapters as follows:In the first chapter,the synthesis of 2,3-dihydrobenzofuran skeleton was introduced in brief,and a comprehensive review on its pertinent research progress was conducted according to different synthetic strategies.In the second chapter,the recent progress of chiral spirocyclic pyrrolidine ligands developed by our group has been highlighted.In continuation with our research interests for the SPD ligands,a series of chiral spirocyclic pyrrolidine ligands was designed and synthesized.And a highly efficient copper-catalyzed asymmetric [3 + 2]cyclization reactions with high yields(up to 96%)and excellent enantioselectivities(up to 99% ee)to construct 2-aryl-2,3-dihydrobenzofuran skeleton has been achieved by using new SPDO catalyst.The total synthesis studies of natural products have been further conducted by using this synthesis methodology as a key step.In the third chapter,based on the previous study,two new iridium complexes with the spirocyclic advantageous skeleton and NHC framework were synthesized and preliminary explorations of its properties were carried out.