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Synthesis of Heterocyclic ring Systems Using Organometallic reagents

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复旦学报（自然科学版） 2005年第5期44卷 699-700页

作者： Sameer Agarwal Jan Knll Micha P. Krahl Hans-Joachim Knlker institut für organische chemie Technische Universitt Dresden Bergstrasse 66 01069 Dresden GermanyInstitut für Organische Chemie Technische Universitt Dresden Bergstrasse 66 01069 Dresden GermanyInstitut für Organische Chemie Technische Universitt Dresden Bergstrasse 66 01069 Dresden GermanyInstitut für Organische Chemie Technische Universitt Dresden Bergstrasse 66 01069 Dresden Germany

We developed novel synthetic routes to heterocyclic ring systems by using transition metal-mediated or -catalyzed reactions. A Lewis acid-promoted addition of the propargyl Grignard reagent 2 to the Schiff base 1 followed by a silvermediated oxidative cyclization of the homopropargylamine 3 provided the aryl-substituted pyrrole 4. Combined with a chemoselective hydrogenation of the pyrrole ring, this method has been applied to the total synthesis of the biologically active fused indolizidine alkaloids ( ± )-harmicine and ( ± )-crispine A[1]. See fig. 1.

关键词：生物碱咔唑杂环有机金属反应物氧化特性钯吡咯

A Sultone route to the Antileukemic 1,10-Seco-Eudesmanolides (-)-Eriolanin and (-)-Eriolangin

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复旦学报（自然科学版） 2005年第5期44卷 730-731页

作者： J. Merten A. Hennig P. Metz institut für organische chemie TU Dresden Bergstr. 66 D-01069 Dresden GermanyInstitut für Organische Chemie TU Dresden Bergstr. 66 D-01069 Dresden GermanyInstitut für Organische Chemie TU Dresden Bergstr. 66 D-01069 Dresden Germany

Isotopic labelling experiments and enzymatic preparation of iso-casbenes with casbene synthase from ricinus communis

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Organic Chemistry frontiers 2022年第3期9卷 795-801页

作者： Heng Li Jeroen S.Dickschat Kekulé-institut für organische chemie und Biochemie Rheinische Friedrich-Wilhelms-Universität BonnGerhard-Domagk-Straße 153121 BonnGermany

Isotopic labelling experiments gave insights into the enzyme mechanism of casbene synthase from ricinus communis,showing a clear stereochemical course for the cyclisation reaction,in agreement with the reported absolute configuration of *** oligoprenyl diphosphate analogs with shifted double bonds were synthesised and enzymatically converted with casbene synthase to yield casbene isomers.

关键词： enzymatic isomers bonds

rhodaelectro-Catalyzed C–H and C–C Activation

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CCS Chemistry 2021年第2期3卷 1529-1552页

作者： Youai Qiu Cuiju Zhu Maximilian Stangier Julia Struwe Lutz Ackermann institut für organische und Biomolekulare chemie Georg-August-Universität GöttingenGöttingen 37077

rhodium(III)catalysis has set the stage for a plethora of oxidative C–H functionalizations over the last decade,which have predominantly employed stoichiometric amounts of toxic and expensive metal oxidants,such as silver(I)*** the meantime,electrosynthesis has emerged as an increasingly viable alternative for expensive and toxic ***,significant momentum has been achieved with the merger of electrocatalysis with organometallic C–H ***,user-friendly and robust rhodaelectro-catalysis has until very recently proven elusive for oxidative C–H *** minireview highlights the current knowledge and recent advances of electrooxidation in rhodium-catalyzed C–H or C–C activations,with a topical focus on contributions from the Ackermann group through July 2020.

关键词： electrosynthesis rhodium catalysis C–H activation C–C activation mechanistic in-sights rhodaelectro-catalysis

Orbital deletion procedure and its applications

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Science China Chemistry 1999年第3期42卷 253-260页

作者：莫亦荣林梦海吴玮张乾二 Department of Chemistry Institute of Physical Chemistry and State Key Laboratory for Physical Chemistry on Solid Surface Xiaman University Xiamen China Computer chemie Centrum Institut für Organische Chemie Universität Erlangen-Nürnberg Erlangen Germany

The orbital deletion procedure is introduced, which is suited to quantitatively investigating the electronic delocalization effect in carbocations and boranes. While the routineab initio molecular orbital methods can generate wavefunctions for real systems where all electrons are delocalized, the present orbital deletion procedure can generate wavefunctions for hypothetical reference molecules where electronic delocalization effect is deactivated. The latter wave-function normally corresponds to the most stable resonance structure in terms of the resonance theory. By comparing and analyzing the delocalized and the localized wavefunctions, one can obtain a quantitative and instinct picture to show how electronic delocalization inside a molecule affects the molecular structure, energy as well as other physical properties. Two examples are detailedly discussed. The first is related to the hyperconjugation of alkyl groups in carbocations and a comparison of the order of stability of carbocations is made. The second concerns the Lewis acidity of boron trihalides where the conjugation effect among the doubly-occupied π atomic orbitals on the halide atoms and the vacant π atomic rbital on the boron atom plays a dominant role in determining the relative acceptor properties. The results demonstrate that the orbital deletion procedure can be used to very successfully interpret some traditional chemical intuitions and concepts in a quantitative way.

关键词： electronic delocalization orbital deletion procedure carbocation boron trihalide.

Condensation of pyrylium salts with mixed anhydrides:aryl ethers,aryl amines and sterically congested aromatics

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Organic Chemistry frontiers 2022年第2期9卷 294-298页

作者： Daniel Grabowski Susanne Alef Steven Becker Ute Muller Gregor Schnakenburg Sigurd Hoger aKekulé-institut für organische chemie und Biochemie Rheinische Friedrich-Wilhelms-Universität BonnGerhard-Domagk-Str.153121 BonnGermany binstitut für Anorganische chemie Universität BonnGerhard-Domagk-Str.153121 BonnGermany

The condensation of easily accessible and widely functionalizable 2,4,6-triaryl pyrylium salts with mixed anhydrides,formed in situ fromα-functionalized sodium acetates and an anhydride solvent,leads in good yields to the corresponding 2,4,6-triaryl benzenes functionalized at their 1-position.4-(Trifluoromethyl)benzoic anhydride has been proven as being the solvent of choice and ortho-disubstituted diphenyl ethers,triphenyl amines and phenyl carbazoles with different functionalizations are *** addition,sterically hindered anthracene diacetate is condensed with two bis-bromophenyl pyrylium salts which leads after intramolecular Yamamoto coupling to *** these,the anthracene core is surrounded by phenylenes and protected from photooxidation,leading to a highly stable blue emitting material.

关键词： material. anhydride salts

Antitubercular activity of the semi-polar extractives of Uvaria rufa

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Asian Pacific Journal of Tropical Medicine 2012年第10期5卷 777-780页

作者： Allan Patrick G Macabeo florie A Tudla Karsten Krohn Scott G franzblau Organic Synthesis and Phytochemistry Laboratory Research Center for the Natural SciencesUniversity of Santo TomasEspana Blvd.Manila 1015Philippines institut fr organische chemie Universitat RegensburgUniversitatsstrasse 3193053 RegensburgGermany institut fr organische chemie Universitat PaderbornGermany institute for Tuberculosis research College of PharmacyUniversity of Illinois.IL 60085USA

Objective:To investigate the inhibitory activity of the chloroform extract,petroleum ether and chloroform sub-extracts,lead-acetate treated chloroform extract,fractions and secondary metabolites of Uvaria rufa(***) against Mycobacterium tuberculosis(***) H_(37)rv. Methods:The antituberculosis susceptibility assay was earried out using the colorimetric Microplate Alamar blue assay(MABA).In addition,the cytotoxicity of the most active fraction was evaluated using the VErO cell toxicity ***:The in vitro inhibitory activity against *** H_(37)rv increased as purification progressed to fractionation(MIC up to 23μg/mL). The chloroform extract and its sub-extracts showed moderate toxicity while the most active fraction from chloroform sub-extract exhibited no cytotoxicity against VErO ***, the lead acetate-treated crude chloroform extract and its fractions showed complete inhibitions (100%) with MIC values up to 8μg/*** screening of the most active fraction showed,in general,the presence of terpenoids,steroids and phenolic *** of the antimycobacterial activity of known secondary metabolites isolated showed no promising inhibitory activity against the test ***:The present results demonstrate the potential of *** as a phytomedicinal source of compounds that may exhibit promising antituberculosis *** addition,elimination of polar pigments revealed enhanced inhibition against *** H_(37)*** several compounds known for this plant did not show antimycobacterial activity,the obtained results are considered sufficient reason for further study to isolate the metabolites from *** responsible for the antitubercular activity.

关键词： Uvaria rufa Antitubercular Mycobacterium tuberculosis H_(37)rv

Solid-state emissive biphenylene bridged bisaroyl-S,N-ketene acetals as distinct aggregation-induced enhanced emitters and fluorometric probes

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Aggregate

Aggregate 2021年第5期2卷 179-184页

作者： Lukas Biesen Thomas J.J.Muller institut fur organische und Makromolekulare chemie Heinrich-Heine-Universitat DusseldorfDüsseldorfGermany

Biphenylene bridged bisaroyl-S,N-ketene acetals can be readily synthesized by a one-pot Masuda borylation-Suzuki arylation sequence,thus,yielding a library of 20 bisaroyl-S,N-ketene acetals with tunable solid-state emission and aggregationinduced enhanced emission characteristics depending on the para substituents in the starting *** applications as fluorometric probe of alcoholic beverages are outlined.

关键词： aggregation-induced emission aroyl-S N-ketene acetals liquor sensors one-pot reaction solid-state

Cobaltaelectro-Catalyzed C—H Acyloxylation

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Chinese Journal of Chemistry 2019年第6期37卷 552-556页

作者： Cong Tian Uttam Dhawa Julia Struwe Lutz Ackermann institut fur organische und Biomolekulare chemie Georg-August-Universitat GottingenTammannstraβe 237077 GottingenGermany

Cobaltaelectrocatalysis set the stage for sustainable C—H acyloxylations in biomass-derived γ-valerolactone as a renewable solvent. The sustainable electrocatalysis regime featured ample scope, along with high level... 详细信息

关键词： C-H activation cobalt electrosynthesis biomass solvent