共查询到20条相似文献,搜索用时 15 毫秒
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Palladium‐Catalyzed Three‐Component Cascade Reaction: Facial Access to Densely Functionalized Indolizines 下载免费PDF全文
Ren‐Rong Liu Chuan‐Jun Lu Ming‐Di Zhang Jian‐Rong Gao Prof. Dr. Yi‐Xia Jia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7057-7060
A palladium‐catalyzed three‐component cascade reaction of 2‐(2‐enynyl)pyridines with nucleophiles and allyl halides has been developed, enabling the synthesis of densely functionalized indolizines in moderate to good yields. The newly developed methodology offers several practical advantages, including operational simplicity, ready availability of starting materials, and mild reaction conditions. 相似文献
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Highly Enantioselective Intermolecular Cross Rauhut–Currier Reaction Catalyzed by a Multifunctional Lewis Base Catalyst 下载免费PDF全文
Xuelin Dong Ling Liang Erqing Li Prof. Dr. You Huang 《Angewandte Chemie (International ed. in English)》2015,54(5):1621-1624
The highly enantioselective intermolecular cross Rauhut–Currier reaction of different active olefins catalyzed by a multifunctional chiral Lewis base was reported. The RC products were obtained in excellent yields (up to 98 %), high chemo‐ and enantioselectivity (up to 96 % ee). The reaction could be performed on a gram scale using 1 mol % of the multifunctional phosphine catalyst. 相似文献
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Organocatalytic Enantioselective Cross‐Vinylogous Rauhut–Currier Reaction of Methyl Coumalate with Enals 下载免费PDF全文
Qiwen Liu Prof. Dr. Liansuo Zu 《Angewandte Chemie (International ed. in English)》2018,57(30):9505-9509
The organocatalytic enantioselective intermolecular cross‐vinylogous Rauhut–Currier (RC) reaction of methyl coumalate with α,β‐unsaturated aldehydes is reported, and the enals are activated by iminium catalysis to serve as the Michael acceptors and methyl coumalate is used as an activated diene to generate a latent enolate. The excellent selectivity is driven by the aromaticity of methyl coumalate, and the post transformation of this heterocyclic structure into other electron‐deficient arenes and heterocycles have addressed, in part, the challenging selectivity issues of the intermolecular cross‐RC reactions and the limited scope of iminium catalysis. 相似文献
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Jean‐Baptiste Gualtierotti Xavier Schumacher Dr. Patrice Fontaine Dr. Géraldine Masson Dr. Qian Wang Prof. Dr. Jieping Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(46):14812-14819
Mild and general alumina‐promoted hydrolysis conditions for converting α‐iminonitriles into carboxamides have been developed. In combination with the oxidative three‐component Strecker reaction, the one‐pot direct amidation of aldehydes and alcohols is reported. Subsequently, an Yb(OTf)3‐catalyzed Michael addition of thiols to α,β‐unsaturated α‐iminonitriles is reported for the synthesis of β‐mercapto‐α‐iminonitriles. The successful integration of an oxidative Strecker reaction, thio‐Michael addition, and neutral‐alumina‐promoted hydrolysis of β‐mercapto‐α‐iminonitriles into a three‐component one‐pot process allowed us to develop the direct conversion of amines, aldehydes, and thiols into β‐mercaptoamides. All of these procedures were applicable to aromatic and aliphatic amines and aldehydes. 相似文献
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Organocatalyzed Cascade Aza‐Michael/Michael Addition for the Asymmetric Construction of Highly Functionalized Spiropyrazolone Tetrahydroquinolines 下载免费PDF全文
An organocatalyzed diastereo‐ and enantioselective cascade aza‐Michael/Michael addition of 2‐tosylaminoenones to unsaturated pyrazolones has been developed to afford novel chiral spiropyrazolone tetrahydroquinolines containing three contiguous stereocenters. This cascade reaction proceeded well with 2 mol % chiral bifunctional tertiary amine squaramide catalyst to give the desired products in excellent yields (up to 99 %) with excellent diastereoselectivity (up to >25:1 diastereomeric ratio) and high enantioselectivity (up to 91 % enantiomeric excess). 相似文献
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Highly Functionalized Cyclopentane Derivatives by Tandem Michael Addition/Radical Cyclization/Oxygenation Reactions 下载免费PDF全文
Ing. Martin Holan Dr. Radek Pohl Dr. Ivana Císařová Dr. Blanka Klepetářová Prof. Dr. Peter G. Jones Dr. Ullrich Jahn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9877-9888
Densely functionalized cyclopentane derivatives with up to four consecutive stereocenters are assembled by a tandem Michael addition/single‐electron transfer oxidation/radical cyclization/oxygenation strategy mediated by ferrocenium hexafluorophosphate, a recyclable, less toxic single‐electron transfer oxidant. Ester enolates were coupled with α‐benzylidene and α‐alkylidene β‐dicarbonyl compounds with switchable diastereoselectivity. This pivotal steering element subsequently controls the diastereoselectivity of the radical cyclization step. The substitution pattern of the radical cyclization acceptor enables a switch of the cyclization mode from a 5‐exo pattern for terminally substituted olefin units to a 6‐endo mode for internally substituted acceptors. The oxidative anionic/radical strategy also allows efficient termination by oxygenation with the free radical 2,2,6,6‐tetramethyl‐1‐piperidinoxyl, and two C?C bonds and one C?O bond are thus formed in the sequence. A stereochemical model is proposed that accounts for all of the experimental results and allows the prediction of the stereochemical outcome. Further transformations of the synthesized cyclopentanes are reported. 相似文献
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Xingxing Wu Liejin Zhou Rakesh Maiti Chengli Mou Lutai Pan Yonggui Robin Chi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(2):487-491
A carbene and sulfinate co‐catalyzed intermolecular Rauhut–Currier reaction between enals and nitrovinyl indoles is disclosed. The carbene catalyst activates the enal and the sulfinate co‐catalyst activates the nitrovinyl indole. Both activation processes are realized via the formation of covalent bonds between the catalysts and substrates to generate catalyst‐bound intermediates. The dual catalytic reaction affords azepino[1,2‐a]indole products with excellent stereoselectivity. Our study demonstrates the unique involvement of sulfinate as an effective nucleophilic catalyst in activating electron‐deficient alkenes for asymmetric reactions. This dual catalytic approach should also encourage future explorations of both sulfinate and carbene catalysts for new reactions. 相似文献