Studies Of Semipinacol Rearrangement Reaction And Application Of Nitrogen-spirocyclic Catalyst In Asymmetric Reaction

All-carbon quaternary carbons are of important research topic because they are usually important structral motifs in the synthesis of natural products and drug molecules.Semipinacol rearrangement has been widely used in the field of organic synthetic chemistry,especially in the construction of quaternary carbon centers.Tandem reactions that can efficiently construct complex compounds have been widely realized and applied in the synthesis of natural products.We have realized tandem allyl carbocation initiated semipinacol rearrangement and 1,3-dicarbonyl radical addition semipinacol rearrrangement.A series of chiral catalysts and metal ligands were derived from heterocyclic pyrrole?SPD?.Based on the framework of SPD,phosphoric acid catalyst and secondary amine thiourea catalyst were prepared.The secondary amine thiourea catalyst showed excellent catalytic ability in the asymmetric addition reaction of fural aldehyde and unsaturated1,2-dicarbonyl compound.This paper is divided into three chapters:In chapter 1,the background of the semipinacol rearrangement induced by carbon electrophile and the progress of our work are introduced in detail.We used allyl alcohol as the electrophile to realize the allylation semipinacol rearrangement cascade reaction,and the reaction products could be used to obtain the skeletons of two kinds of natural products.In chapter 2,the background of the semipinacol rearrangement induced by free radicals and the progress of our work are introduced in detail.Using manganese acetate and Cu?OTf?₂ as oxidants,we oxidized 1,3-dicarbonyl compounds to free radicals,which were added to the double bonds and induced semipinacol reactions,and substrates of intramolecular and intermolecular were shown to be suitable in this rearrangement tandem reaction.In chapter 3,the background of organic amine catalysis and the background of asymmetric reactions which were catalyzed by SPD catalysts were introduced.Based on the SPD-backbone,we designed and synthesized phosphoric acid and thiourea secondary amine catalysts.After extensive screening of the reaction conditions,the secondary amine thiourea catalyst exhibited excellent catalytic activity and stereoselective control in the addition reaction of furan aldehyde and ketone of unsaturated?-keto ester.The scope of the substrates and futher application of the enantioenriched products in the synthesis of the backbone of nature products were in progress.