Tin Powder Promoted Synthesis Of Oxindoles And Isoindolinones

The 2-oxindole and isoindolinone framework exist in bioactive natural products and compounds with biological and pharmacological activities.Among them,3,3-disubstituted-2-oxindoles are recognized as valuable compounds for drug discovery,and 3,3-disubstituted-isoindolinones are prioritily served as key intermediates for the synthesis of many kinds of drug candidates.Therefore,it is of great significance to develop an efficient and facile approach for the construction of these heterocyclic compounds.On the other hand,Organic reactions promoted by tin powder have been paid more attention in recent years.In our group's research works,we found that tin powder could promoted allylation and cyclization reactions with aldehydes,ketones,imines and acylhydrazones by in-situ generated allyltin bromide.In order to further investigate the organic reaction promoted by tin powder,we developed a new tin powder ptomoted protocol for the synthesis of 3,3-disubstituted-2-oxindoles and 3,3-disubstituted isoindolinones from allylation reactions of 3-hydroxy-2-oxindoles and phthalimides.This thesis is mainly composed of the following three charpters: The chapter one: The research progress of reactions involving carbocationsIn this chapter,we described the research progress of nucleophilic substitution reactions of carbocations with nucleophiles such as enols,enamines,allyl silicon,and the classical organic reactions of carbocations were also involved.The chapter two: Tin powder promoted synthesis of 3,3-disubstituted-2-oxindolesThis chapter reports the coupling reaction of 3-hydroxy-2-oxindoles and allyl bromide promoted by tin powder,and a series of 3,3-disubstituted-2-oxindoles are obtained in high yield.The results showed that the reaction could also proceed smoothly when benzyl alcohol and 3-hydroxy-isoindolinone were used as substrates.It is the first time that the nucleophilic substitution reaction promoted by tin powder were achieved.it has the advantages of simple operation and mild conditions,which also provides a new method for the snythesis of 3,3-disubstituted-2-oxindoles derivatives and further extends the application of tin powder promoted reactions in organic synthesis.The chapter three: Tin powder promoted synthesis of 3,3-disubstituted isoindolinonesIn this chapter,A efficient one-pot reaction was developed for the synthesis of 3,3-disubstituted isoindolinones from the reactions of phthalimides and allylic bromide promoted by tin powder in the presence of TsOH in tetrahydrofuran under reflux.The method avoids the use of toxic stannanes and has the advantages of the environmental friendliness and high yield,which provides a new method for the snythesis of 3,3-disubstituted-isoindolinones...