Development Of 1-phosphanorbornene Chiral Phosphine Catalysts And Research On Reaction Performance

Chiral phosphorus catalysts have been rapidly developed in the past few decades.Chemists have designed various kinds of chiral phosphorus catalysts,which are applied to the asymmetric catalysis fields,and achieved excellent catalytic effects.However,most chiral phosphorus catalysts are designed based on the carbon chiral frameworks,and there are relatively few reports about chiral phosphorus catalysts with phosphorus chiral centers.Moreover,P-chirogenic catalysts possess chirality centers at the phosphorus atoms,the phosphorus center can be closer to the reaction site during the reaction process,increasing the possibility of its chirality induction and transmission,in which may develop new reaction modes or expand the universality of substrates in the field of asymmetric catalysis.Therefore,based on the unique catalytic properties of these chiral phosphorous catalysts,we used cheap and easily available chiral tert-butylsulfinamide to induce the chirality of the bridgehead phosphorus of the 1-phosphanorbomene skeleton,and synthesized a series of new P-chirogenic catalysts,which was called Jia Phos.This new type of chiral phosphorus catalyst could be synthesized in simple 5 steps,and avoided the use of chiral reagents for resolution.This pair of diastereomers with P-chirogenic centers are separated by simple column chromatography.In order to verify the catalytic activity of Jia Phos,it was applied to the asymmetric phosphine-catalyzed annulations of y-substituted allenes,and realized the enantioselective(4+2)annulations involving 3-methylene-2-oxindoles with y-substituted allenoates,providing a wide range of 3,3’-spirocyclic oxindoles.When this pair of diastereomeric chiral phosphorus catalysts J-5a and J-5a’ were used to catalyze the reaction,we got spiro products with completely opposite configurations,both of which have good substrate applicability and excellent enantioselectivity and efficiency.