Regio-and Stereoselective [3+2] Cycloaddition Reactions Involving The 3-Aminooxindole Synthon

As a powerful synthetic tool,the 1,3-dipolar cycloaddition reaction plays a very important role in the construction of heterocyclic compounds.As one class of 1,3-dipoles,the cycloaddition reaction of azomethine ylide species and dipoleophiles has been extensively reported so far.In general,the reaction is used to construct important nitrogen-containing heterocyclic compoundsSpirooxindoles are an important class of potentially bioactive compounds existing in a wide range of natural and pharmaceutical molecules.In recent years,the syntheses of these compounds and their activity research have attracted considerable attention from synthetic organic chemists and biologists.To date,a variety of synthetic methods for the synthesis of such compounds have been established.Among these,the cycloaddition reaction of azomethine ylides constitutes one of the most important methods.The focus of this dissertation is on the stereoselective construction of spirooxindoles by exploiting the reactivity of 3-aminooxindole derived azomethine ylides in[3+2]cycloaddition reactions.The main contents of this thesis include the following four parts.1.A catalytic asymmetric construction of spirooxindoles through chiral phosphoric acid-catalyzed 1,3-dipolar cycloaddition involving 3-aminooxindoles and nitroolefins was developed.This reaction gave the desired products with high yields and excellent stereoselectivities under mild reaction conditions(up to 99%yield,>20:1 dr,and>99%ee).2.A catalytic asymmetric construction of spirooxindoles through chiral phosphoric acid-catalyzed 1,3-dipolar cycloaddition involving 3-aminooxindoles and ?,?-enones was established.This reaction gave novel cycloadducts in high yields with excellent regio-and stereoselectivites as well as wide substrates scope under mild reaction conditions(up to 99%yield,>20:1 rr,and>99%ee).Notably,a series of spirooxindoles bearing the 3 4-dihydro-2H-pyrrole motif was readily accessed by oxidative dehydrogenation,and the epimer of the original cycloadduct could be easily obtained by reduction of the dihydropyrroles.3.A catalytic asymmetric construction of 2,5-dihydropyrrolidine spirooxindoles through chiral phosphoric acid-catalyzed 1,3-dipolar cycloaddition involving 3-aminooxindole hydrochlorides,and ?,?-ynones was achieved.This reaction gave 2,5-dihydropyrrole-fused spirooxindoles with high yields and excellent stereoselectivites as well as wide substrate scope under mild reaction conditions(up to 99%yield,>20:1 dr,and>99%ee).Notably,a series of spiro[pyrrole-oxindoles]was easily produced by dehydrogenation of the cycloadducts.4.A direct assembly of indolenines,3-amino oxindoles,and aldehydes into indolenine-substituted spiro[pyrrolidine-2,3'-oxindoles]via 1,3-dipolar cycloaddition was developed,affording high yields and good to excellent diastereoselectivities under mild reaction conditions(up to 99%yield,>20:1 dr).Notably,diastereocontrol could be easily tuned by slightly changina the reaction conditions.