共查询到20条相似文献,搜索用时 15 毫秒
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Copper‐Catalyzed (2+1) Annulation of Acetophenones with Maleimides: Direct Synthesis of Cyclopropanes 下载免费PDF全文
Srimanta Manna Dr. Andrey P. Antonchick 《Angewandte Chemie (International ed. in English)》2015,54(49):14845-14848
A practical copper‐catalyzed direct oxidative cyclopropanation of electron‐deficient alkenes with acetophenone derivatives is reported. The dehydrogenative annulation involves a double C? H bond functionalization at the α‐position of the ketone using di‐tert‐butyl peroxide as oxidant. The broad scope of the reaction and excellent functional‐group tolerance is demonstrated for the stereoselective synthesis of fused cyclopropanes. The developed transformation revealed an unprecedented reactivity for copper‐catalyzed processes. 相似文献
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Yao Xu Michael L. Conner Prof. M. Kevin Brown 《Angewandte Chemie (International ed. in English)》2015,54(41):11918-11928
Cyclobutanes and cyclobutenes are important structural motifs found in numerous biologically significant molecules, and they are useful intermediates for chemical synthesis. Consequently, [2+2] cycloadditions to access cyclobutanes and cyclobutenes have been established to be particularly useful transformations. Within the last 10 years, an increase in the frequency of publications for catalytic enantioselective [2+2] cycloadditions has occurred. These reactions provide access to a wide array of enantiomerically enriched chemical diversity that was not previously attainable. Described in this review are the advances made in catalytic enantioselective [2+2] cycloadditions to access cyclobutanes and cyclobutenes. 相似文献
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Prof. Dr. Benito Alcaide Prof. Dr. Pedro Almendros Carlos Lázaro-Milla 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7547-7552
A regioselective synthesis of general applicability has been designed for the one-pot preparation of 2,3-disubstituted-cyclobutenones from iodoalkynes through cyclobutenylation, Suzuki CC coupling, and ketone formation. This one-pot methodology has been applied to the selective synthesis of an orally active cyclooxygenase II inhibitor. Furthermore, the obtained cyclobut-2-en-1-ones were used as synthons in several transformations, such as, the preparation of β-lactams, phthalazines, cyclohexa-2,5-dien-1-ones, and cyclopent-3-en-1-ones. 相似文献
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Marek I 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(25):7460-7468
The current state-of-the-art synthesis for the formation of enantiomerically enriched all-carbon quaternary stereocenters in acyclic system relies on the formation of a single carbon-carbon bond per chemical step by asymmetric catalysis. These extraordinary sophisticated methods were logically classified among the most powerful and innovative ones. In this concept article, we are proposing a new retrosynthetic paradigm to solve differently such challenging problems. These new synthetic pathways lead to the diastereo- and enantiomerically pure formation of three new carbon-carbon bonds in acyclic system, in a one-pot reaction, including the formation of all-carbon quaternary stereocenters by using classical reagents and experimental conditions and from common starting materials. 相似文献
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Jan Bornholdt Dr. Jakob Felding Dr. Rasmus P. Clausen Dr. Jesper L. Kristensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(41):12474-12480
The pyrimidine‐2‐sulfonyl (pymisyl) group is introduced as a new protecting group that can be used to activate aziridines towards ring opening. It is readily introduced and removed under mild conditions. Regioselective ring opening of pymisyl‐protected 2‐methyl‐aziridine with organocuprates gives the corresponding sulfonamides in high yields, and the pymisyl group can subsequently be removed upon treatment with a thiolate. The versatility of this new nitrogen protecting group is illustrated with a new synthesis of Selegiline, a monoamine oxidase‐B inhibitor marketed for the treatment of Parkinson’s disease. 相似文献
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[reaction: see text] Allylic ethers are converted to the corresponding alcohol or phenol in virtually quantitative yield at temperatures below ambient simply by stirring a hydrocarbon solution of the ether with 1 molar equiv of tert-butyllithium. The reaction, which produces 4,4-dimethyl-1-pentene as a coproduct, most likely involves an S(N)2' attack of the organolithium on the allyl ether. 相似文献
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Stefano Barranco Federico Cuccu Dayi Liu Dr. Sylvie Robin Dr. Régis Guillot Prof. Dr. Francesco Secci Dr. Valérie Brenner Dr. Michel Mons Prof. Dr. Pierluigi Caboni Prof. Dr. David J. Aitken Prof. Dr. Angelo Frongia 《European journal of organic chemistry》2023,26(16):e202300183
A stereoselective one-pot double derivatization of cyclobutene-1-carboxylic acid via a mild organic base catalyzed amidation/aza-Michael addition of benzo[d]oxazol-2(3H)-ones has been developed. This unprecedented tandem reaction provides access to novel β-N-heterocyclic cyclobutane carboximide derivatives with a trans geometry. The carboximide moiety reacts smoothly with nucleophiles, allowing access to diverse derivatives of trans-β-N-heterocyclic cyclobutanecarboxylic acid, including peptidomimetic structures. 相似文献
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Enantioselective Copper‐Catalyzed Decarboxylative Propargylic Alkylation of Propargyl β‐Ketoesters with a Chiral Ketimine P,N,N‐Ligand 下载免费PDF全文
Fu‐Lin Zhu Yuan Zou De‐Yang Zhang Ya‐Hui Wang Xin‐Hu Hu Song Chen Prof. Dr. Jie Xu Prof. Dr. Xiang‐Ping Hu 《Angewandte Chemie (International ed. in English)》2014,53(5):1410-1414
The first enantioselective copper‐catalyzed decarboxylative propargylic alkylation has been developed. Treatment of propargyl β‐ketoesters with a catalyst, prepared in situ from [Cu(CH3CN)4BF4] and a newly developed chiral tridentate ketimine P,N,N‐ligand under mild reaction conditions, generates β‐ethynyl ketones in good yields and with high enantioselectivities without requiring the pregeneration of ketone enolates. This new process provides facile access to a range of chiral β‐ethynyl ketones in a highly enantioenriched form. 相似文献
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Treatment of 1-benzyl-2-(bromomethyl)aziridine, and some aryl substituted analogues, with an excess of iodomethane resulted in N-allyl-N-benzyl-N,N-dimethylammonium salts, in good yields. These quaternary allylammonium salts are of importance in different fields, from organic synthesis and polymeric chemistry to agricultural use. 相似文献
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Dr. Rebecca L. Davis Dr. Julian Stiller Dr. Tricia Naicker Dr. Hao Jiang Prof. Dr. Karl Anker Jørgensen 《Angewandte Chemie (International ed. in English)》2014,53(29):7406-7426
Chiral epoxides serve as versatile building blocks in the synthesis of complex organic frameworks. The high strain imposed by the three‐membered ring system makes epoxides prone to a variety of nucleophilic ring‐opening reactions. Since the development of the Sharpless epoxidation, there have been many important contributions and advances in this area. With the rapid development of the field of asymmetric organocatalysis, a wide range of organocatalysts is now able to catalyze the epoxidation of broad class of unsaturated carbonyl compounds. In this Minireview, recent progress in the development of organocatalytic asymmetric epoxidation methods, the proposed mechanisms of these reactions and their applications as intermediates is reported. 相似文献