Pd(?) Metal-Catalyzed Asymmetric Synthesis Of Alicyclic Ketone-Based Aromatic Hydrocarbon Derivatives

Styrene is one of the most important raw materials for the synthesis of various organic compounds in nature,so it is a good potential cornerstone in chemical synthesis.Chiral compounds are widely used in biologically active compounds and asymmetric catalysis.Their chirality comes from high steric axial rotation rather than chiral compounds with four different substituents.This characteristic has been paid more and more attention by chemists.In the known axial chiral structure,most of the chiral shafts are located between two aromatic groups,which are called diaryl blocking isomers.Axonal chiral styrene compounds can be used as potential chiral catalysts,ligands or substrate to induce selectivity in the process of chemical transformation.Therefore,the development of enantioselective synthesis methods of these axonal chiral styrene is an important topic in organic chemistry.The enantioselective structure of axonal chiral styrene is still a difficult challenge in modern organic synthesis,which is different from the synthesis method of diaryl blocking isomers.Due to the lower configuration stability of vinylarenes,arsing from the relatively lower rotational barriers,their catalytic asymmetric synthesis remains a daunting task.Oxindoles moiety are privileged framework of natural products and building blocks for bioactive molecules as well as pharmaceuticals.The asymmetric synthesis of axial chiral vinylarenes fearturing oxindole moiety via sequential carbopalladation/C-H olefination or suzuki-miyaura cross-coupling from readily available materials with palladium catalysis has been developed.After the template reaction was successfully established,the factors such as ligands,reaction temperature,palladium sources of catalysts,additives,reaction solvents and so on were studied deeply by experimental method,and the optimum conditions of the reaction system were determined.Under the optimal conditions,the adaptability of the substrate was studied,and 95%high yield and 61%medium ee were obtained.The erosion of optical purity was not observed even after heating the product for 10 h at 110 ~oC,which indicates the excellent stability of the chiral axial.