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Tertiary Amine(Phosphine) Catalyzed Cycloaddition Reactions Based On Active Azo And Imine Compounds

Posted on:2017-02-03Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:2271330485459036Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
Heterocyclic skeletons are very important structural units of bioactive molecules, which used in medicinal chemistry and advanced functional materials.During the past decades, organic base-catalyzed cycloaddition, has been proven as an efficient method to afford cyclic products from easily available starting materials.Meanwhile, various of electrophiles, such as alkenes, imins, aldehydes, azomethine imines, ylides and aziridines, reacted with electron-deficient alkynes or allenoates to form a wide range of carbo- and heterocycles in the presence of organic base.However, there are few reports about using active azo compounds as the electrophile in cyclizations. In this thesis, we mainly study using active azo as new electrophile for expanding the range of substrate in tertiary amine(phosphine) catalyed cyclizations,and constrution cyclic compound containing double(multi) hetero atom with one-step reaction. On the other hand, we also fouces on the study of annulation based active imines as electrophile. The detailed research contents include the following three aspects:(1) We developed highly efficient n Bu3P-catalyzed desulfonylative [3+2]cycloadditions of arylazosulfones(as new electrophile) with Morita-Baylis-Hillman(MBH) carbonates for the synthesis of pyrazole derivatives. The reactions proceed smoothly under mild conditions to generate corresponding annulation products in good to excellent yields. This protocol has advantages of using available starting materials and simple manipulation.(2) We developed a direct synthetic method for the preparation of1,3,4-oxadiazins via a DMAP-catalyzed [2+4] cycloaddition of N-acyldiazenes(as new electrophile) with allenoates. The reactions generated the corresponding products with good yields in most cases under simple and mild reaction conditions. And this organic base-catalyzed one-step cycloaddition reaction generated three heteroatoms ina six-membered ring, providing new synthetic protocols for further heterocyclic synthesis.(3) We developed a mild, environmentally benign protocol for the synthesis of fully functionalized 1,2-dihydropyridine-3,5-dicarbonitrile derivatives by [2+2+2]cycloaddition of N-tosylimine and cyanoacetylene. The cyclization product could be further extended to synthesis of fully substituted pyridines by desulfonylation reaction in nearly quantitative yields under facile conditions.
Keywords/Search Tags:tertiary amine(phosphine), electrophiles, azocompounds, cycloaddition
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