Lewis Acid Catalyzed Annulation of Cyclopropane Carbaldehydes and Aryl Hydrazines: Construction of Tetrahydropyridazines and Application Toward a One-Pot Synthesis of Hexahydropyrrolo[1,2-<i>b</i>]pyridazines
作者:Raghunath Dey、Pankaj Kumar、Prabal Banerjee
DOI:10.1021/acs.joc.8b00332
日期:2018.5.18
In this report, a facilesynthesis of tetrahydropyridazines via a Lewis acid catalyzed annulation reaction of cyclopropane carbaldehydes and aryl hydrazines has been demonstrated. Moreover, the generated tetrahydropyridazine further participated in a cycloaddition reaction with donor–acceptor cyclopropanes to furnish hexahydropyrrolo[1,2-b]pyridazines. We also performed these two steps in one pot in
在该报告中,已经证明了通过路易斯酸催化的环丙烷甲醛和芳基肼的环合反应可轻松合成四氢哒嗪。此外,生成的四氢哒嗪进一步与供体-受体环丙烷一起参与环加成反应,提供六氢吡咯并[1,2- b ]哒嗪。我们还在一个锅中以连续的方式执行了这两个步骤。另外,六氢吡咯并[1,2- b ]哒嗪的单脱羧反应得到了良好的收率。
Lewis Acid Catalyzed Diastereoselective Cycloaddition Reactions of Donor–Acceptor Cyclopropanes and Vinyl Azides: Synthesis of Functionalized Azidocyclopentane and Tetrahydropyridine Derivatives
作者:Raghunath Dey、Prabal Banerjee
DOI:10.1021/acs.orglett.6b03276
日期:2017.1.20
Lewisacidcatalyzed [3 + 2]-cycloaddition reaction of donor–acceptor cyclopropanes with vinyl azides has been developed to obtain diastereomerically enriched azidocyclopentane derivatives. In addition, thermal chemoselective ring expansion of azidocyclopentanes to tetrahydropyridine derivatives and further diastereospecific reduction to a substituted piperidine derivative, with an excellent yield
(4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones
作者:Stefano Nicolai、Jérôme Waser
DOI:10.1002/anie.202209006
日期:2022.9.5
Azepanones are important and widespread seven-membered heterocycles, but their synthesis is challenging. A convergent method to access these scaffolds was developed relying on a (4+3) annulation reaction of azadienes and donor-acceptor cyclopropanes. Good to excellent yields and high diastereoselectivity were achieved using Yb(OTf)3 as the catalyst. Asymmetric induction was possible with Cu(OTf)2 in
Ring Expansion of Donor–Acceptor Cyclopropane via Substituent Controlled Selective <i>N</i>-Transfer of Oxaziridine: Synthetic and Mechanistic Insights
A distinctive N-substituent controlled electrophilic N-transfer of oxaziridines with donor-acceptor cyclopropanes in the presence of MgI2 is reported. Contrary to earlier reports, the oxaziridine having bulkier N-substituents can also give N-transferred product instead of the O-transferred one. Interestingly, the oxaziridines having alpha-H containing N-substituents lead to the pyrrolidine derivatives through [3 + 2] cycloaddition. A mechanistic reasoning for this divergent reactivity 18 depicted by density functional theory calculations and validated through energy decomposition analysis.