نتایج جستجو برای: aza michael reaction

تعداد نتایج: 438931  

Journal: :Chemical communications 2014
Shaoxia Lin Ling Li Fushun Liang Qun Liu

A novel and efficient method for the construction of γ-lactams with an all-carbon quaternary center is developed via a DABCO-catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-deficient alkenes. The process involves sequential ring-opening of activated cyclopropanes, intermolecular Michael addition and intramolecular aza-cyclization.

Journal: :Chemical communications 2012
Jochem P A Rutters Yvette Verdonk Remko de Vries Steen Ingemann Henk Hiemstra Vincent Levacher Jan H van Maarseveen

A new method is presented to prepare strained lactams. Esterification of the C-terminus of a dipeptide with β-nitrostyrene or quinoline-type auxiliaries is followed by lactam formation by an intramolecular aza-Michael-acyl-transfer reaction cascade. Ultimately, the cyclic tetrapeptide cyclo[Phe-Tyr-Ala-Gly] has been prepared.

Journal: :Chemical communications 2011
Jun Jiang Yunfei Cai Weiliang Chen Lili Lin Xiaohua Liu Xiaoming Feng

The catalytic asymmetric aza-Michael reaction of benzoyl hydrazine toward chalcones through the nonactivated amine moiety conjugated addition was facilitated by the developed N,N'-dioxide-Sc(OTf)(3) complex under mild conditions, affording the pharmacologically and synthetically useful products in moderate to high yields with up to 97% ee.

Journal: :Organic & biomolecular chemistry 2012
Laura L Taylor Frederick W Goldberg King Kuok Mimi Hii

An optically active tetrahydroquinoline intermediate (5) was prepared in 8 steps from monoprotected ethylene glycol, using a Pd-catalysed aza-Michael reaction to induce chirality. This can be transformed into three Galipea alkaloids (angustureine, galipeine and cuspareine). The proximity of a benzyloxy group is found to exert profound effects in several steps of the synthesis.

2014
Marcus Blümel Pankaj Chauhan Robert Hahn Gerhard Raabe Dieter Enders

A low loading of a quinine-derived squaramide efficiently catalyzes the triple-domino Michael/aza-Henry/cyclization reaction between 1,3-dicarbonyl compounds, β-nitroolefins, and aldimines to provide tetrahydropyridines bearing three contiguous stereogenic centers in good yields, excellent enantiomeric excesses, and up to high diastereomeric ratios.

Journal: :Organic & biomolecular chemistry 2014
Jiajia Guo Xiaoyang Sun Shouyun Yu

An efficient and diastereoselective strategy based on an intramolecular domino aza-Michael/Darzens reaction to synthesize epoxide-fused benzoquinolizidines has been described. Three bonds (1 C-C, 1 C-N and 1 C-O), three rings and three chiral centers can be constructed in a single pot under very mild conditions. All the products were isolated in only one diastereomer with 40-80% yields.

Journal: :Chemical communications 2014
Etienne Pair Christophe Berini Romain Noël Morgane Sanselme Vincent Levacher Jean-François Brière

We discovered a novel organocatalysed multicomponent domino Knoevenagel-aza-Michael-cyclocondensation reaction leading to an unprecedented straightforward synthesis of 1,5-diazabicyclo[3.3.0]octane-2,6-diones. The specific capability of the (DHQ)2PHAL organocatalyst in this process was also highlighted to eventually furnish the corresponding bicyclopyrazolidinones with up to 96 : 4 er.

Journal: :Organic letters 2012
Biao Jiang Jue Wang Zuo-gang Huang

A stereocontrolled strategy toward the synthesis of nagelamide K has been developed. The dimeric imidazole acrylate, diimidazolidenesuccinate, was constructed as a synthetic precursor by a Ni-catalyzed coupling reaction; the microwave-promoted intramolecular aza-Michael addition afforded the imidazo[1,5-a]pyridine core structure of nagelamide K in high stereoselectivity. A detaurine-dediamino a...

Journal: :The Journal of organic chemistry 2010
Jiang Weng Yong-Bo Li Rui-Bin Wang Feng-Quan Li Can Liu Albert S C Chan Gui Lu

A short and practical synthesis of oseltamivir was accomplished in 11 steps from inexpensive and abundant diethyl D-tartrate starting material. This azide-free route featured an asymmetric aza-Henry reaction and a domino nitro-Michael/Horner-Wadsworth-Emmons (HWE) reaction as the key steps to construct the relevant cyclohexene ring of the product, which provided an economical and practical alte...

Journal: :Tetrahedron 2009
Dinesh Kumar Rayabarapu Aihua Zhou Kyu Ok Jeon Thiwanka Samarakoon Alan Rolfe Hina Siddiqui Paul R Hanson

The development of new methods to skeletally diverse sultams based on a central α-halo benzene sulfonamide building block is reported. Several salient features of this building block are utilized in multiple reaction pathways, including the Heck reaction, C- and O-arylation, Sonogashira-Pauson-Khand, Sonogashira-intramolecular hydroamination, lithiative cyclization and domino aza-Michael Heck f...

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