Studies On The Synthesis Of Fawcettimine And Cascade Reaction Of Umpolung Alkynyl Aldehydes Catalyzed By NHC

This dissertation is on the studies of syntheses of Fawcettimine,one natural product of Lycopodium alkaloids.Meanwhile, we also explored the cascade reaction of alkynyl aldehydes which catalyzed by N-hetereocyclic carbene.There are three parts of this dissertation:Chapter1:N-hetereocyclic carbene catalysis in total synthesis (Review)The recent applications of NHC catalysis in the construction of natural products were summarized.And for its high level of stereoselectivity in bond-forming through Umpolung transformations,it will be a powerful method in organic synthesis.Chapter2:Studies on the synthesis of Lycopodium alkaloids FawcettimineThe progress in synthesis of Fawcettimine were briefly described.And on the basis of previous work,we designed two efficient synthetic routes,which use cascade reaction as the key step. This laid a foundation of synthesis of Fawcettimine-type Lycopodium alkaloids.Chapter3:Studies on cascade reaction of umpolung alkynyl aldehydes catalyzed by N-hetereocyclic carbeneThe mechanism of umpolung alkynyl aldehydes catalyzed by N-hetereocyclic carbene was briefly described.Two different umpolungs (a1-d1and a3-d3) of alkynyl aldehydes were achived by the same NHC catalyst.And the cascade reaction was presented.