Synthesis of Hexahydrobenzo[<i>b</i>]pyrimido[4,5-<i>h</i>][1,6]naphthyridines via an Intramolecular Hetero-Diels−Alder Reaction
作者:Fengzhi Yang、Lianyou Zheng、Jinbao Xiang、Qun Dang、Xu Bai
DOI:10.1021/cc100018b
日期:2010.7.12
Method development was completed for a strategy to access a novel pyrimidine-fused heterocyclic scaffold. The key step for this synthetic route entails an intramolecular inverse electron demand hetero-Diels-Alder reaction of imines or iminiums formed in situ from allylaminopyrimidinealdehydes 3 and anilines. The reactions provided exclusively cis-configuration products 6. Products 6 were readily precipitated
Simple aromatic substituents in the substrate molecule, including pyrimidine, pyridine, and benzene rings, directly facilitated the intramolecular cycloaddition of azomethine ylide to alkene. All of these aromatic substituents aided the formation of azomethine ylides, which then underwent highly diastereospecific sequential cycloaddition. It was shown that both the presence of an electron-deficient
On-Demand Selection of the Reaction Path from Imino Diels-Alder to Ene-Type Cyclization: Synthesis of Epiminopyrimido[4,5-<i>b</i>]azepines
作者:Yuewei Zhang、Yue Zhu、Lianyou Zheng、Lian-Gang Zhuo、Fengzhi Yang、Qun Dang、Zhi-Xiang Yu、Xu Bai
DOI:10.1002/ejoc.201301318
日期:2014.1
selection of the final products from the same starting materials. The successful execution of such a strategy will reduce the time required to prepare diverse scaffolds. The imines derivedfrom 4-(allylamino)pyrimidine-5-carbaldehydes and anilines undergo Diels–Alder reactions to give pyrimido[4,5-h][1,6]naphthyridines in high yields. A complete switch from the intramolecular aza-Diels–Alder (IADA) path
A Highly Stereocontrolled Intramolecular Cycloaddition Reaction of Azomethine Ylide Activated by a Pyrimidine Ring: Access to Novel Tricyclic Hexahydro-1H-pyrrolo[2′,3′:4,5]pyrido[2,3-d]pyrimidines
作者:Qun Dang、Xu Bai、Hongxiang Xie、Jinbao Xiang
DOI:10.1055/s-0031-1290333
日期:2012.3
formation of an azomethineylide undergoing intramolecularcycloaddition reactions. This method enabled efficient synthesis of a novel tricyclic pyrimidine-piperidine-pyrrolidine scaffold from various pyrimidinemethyl amines and aldehydes in complete stereocontrol and could be rationalized by an S-shaped azomethineylide intermediate. azomethineylide - intramolecularcycloaddition - 1,3-dipolar cycloaddition