Accessing Dihydro-1,2-oxazine via Cloke–Wilson-Type Annulation of Cyclopropyl Carbonyls: Application toward the Diastereoselective Synthesis of Pyrrolo[1,2-<i>b</i>][1,2]oxazine
作者:Pankaj Kumar、Rakesh Kumar、Prabal Banerjee
DOI:10.1021/acs.joc.0c00531
日期:2020.5.15
A convenient additive-free synthesis of dihydro-4H-1,2-oxazines via a Cloke-Wilson-type ring expansion of the aryl-substituted cyclopropane carbaldehydes with the hydroxylamine salt is introduced. Comparatively less active cyclopropyl ketones also follow a similar protocol if supplemented by catalytic p-toluene sulfonic acid monohydrate. The transformation is performed in an open-to-air flask as it
Rhodium-Catalyzed Cyclopropanation of Alkenes with Dimethyl Diazomalonate
作者:Francisco González-Bobes、Michaël D. B. Fenster、Susanne Kiau、Laxma Kolla、Sergei Kolotuchin、Maxime Soumeillant
DOI:10.1002/adsc.200800027
日期:2008.4.7
α′-tetramethyl-1,3-benzenedipropanoate] to catalyze the cyclopropanation of a wide range of alkenes with malonate-derived carbenoids under mild reaction conditions is reported in this communication. The experimental protocol is remarkably simple, uses readily accessible and stable dimethyldiazomalonate with very low catalyst loading. More importantly, the alkene is employed as a limiting reagent.
Reaction of donor-acceptor cyclopropanes with 1,3-diphenylisobenzofuran. Lewis acid effect on the reaction pathway
作者:A. O. Chagarovskiy、O. A. Ivanova、E. M. Budynina、E. L. Kolychev、M. S. Nechaev、I. V. Trushkov、M. Ya. Mel’nikov
DOI:10.1007/s11172-013-0349-x
日期:2013.11
Sn(OTf)2, SnCl2, ZnCl2, GaCl3, and MgI2, proceeds as a formal [3+4]-cycloaddition leading to a newly formedseven-memberedring. This reaction was found to be typical of cyclopropane-1,1-diesters and dinitriles, as well as 1-nitrocyclo-propanecarboxylates containing aromatic, heteroaromatic, and vinylicsubstituents at the C(2) atom of the small ring. When Me3SiOTf, TiCl4, SnCl4, or BF3·OEt2 were used as initiators
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。
Synthesis of Indenopyridine Derivatives <i>via</i>
MgI<sub>2</sub>
-Promoted [2+4] Cycloaddition Reaction of <i>In-situ</i>
Generated 2-Styrylmalonate from Donor-Acceptor Cyclopropanes and Chalconimines
作者:Kamal Verma、Prabal Banerjee
DOI:10.1002/adsc.201800598
日期:2018.10.4
An unexpected MgI2‐promoted [2+4] cycloaddition reaction of in‐situ generated 2‐styrylmalonate from donor‐acceptor cyclopropanes with chalconimines to synthesize highly substituted indenopyridine derivatives under the mild reaction conditions have been developed. Additionally, these derivatives were utilized for the synthesis of highly substituted 9‐membered lactam by oxidative C=C bond cleavage and