- Lithium perchlorate-, acetic anhydride-, and triphenylphosphine-assisted multicomponent syntheses of 4-unsubstituted 2,5-dioxooctahydroquinoline-3- carboxylates and 3-carbonitriles
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Lithium perchlorate and acetic anhydride were the key additives for the multi-component reaction between 3-aminocyclohex-2-enones, formaldehyde, and malonates yielding adducts that were annulated under acidic conditions to afford bicyclic 2,5-dioxooctahydroquinoline-3-carboxylates. When methyl cyanoacetate was subjected to the same reaction conditions in the presence of a catalytic amount of triphenylphosphine, the bicyclic 2,5-dioxooctahydroquinoline-3- carbonitriles were obtained in a one-flask reaction.
- Gu, Xingxian,Georg, Gunda I.
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- Synthesis and Properties of Carbaporphyrin and Carbachlorin Dimethyl Esters Derived from Cyclopentanedialdehydes
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Norbornenes with two ester substituents were prepared by Diels-Alder cycloadditions of cyclopentadiene with dimethyl fumarate and dimethyl 1,1-ethylenedicarboxylate. Oxidation with potassium permanganate gave good yields of related diols that were oxidatively ring-opened to afford cyclopentane dialdehydes. MacDonald-type "3 + 1" condensations with a tripyrrane, followed by oxidation with DDQ in refluxing toluene, gave carbaporphyrin or carbachlorin products in good yields. The macrocyclic products were highly diatropic and produced porphyrin-like UV-vis spectra. The carbaporphyrin was converted into silver(III) and gold(III) organometallic derivatives. Reaction with methyl iodide in the presence of potassium carbonate gave mono- and dialkylation products, and treatment of the former with Ni(OAc)2 or Pd(OAc)2 afforded nickel(II) and palladium(II) complexes. The free base carbaporphyrin and carbachlorin, and the nickel and palladium complexes, were characterized by X-ray crystallography. The carbachlorin also reacted with silver(I) acetate to give a silver(III) derivative. Carbaporphyrins and carbachlorins underwent deuterium exchange at the meso-positions with deuteriated TFA, and this observation indicates that protonation is occurring at the bridging carbons. The new route to carbaporphyrins and carbachlorins has enabled detailed studies on the properties of these systems and provides the foundations for future investigations.
- Sahota, Navneet,Ferrence, Gregory M.,Lash, Timothy D.
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- Total Synthesis of the Meroterpenoid Manginoid A as Fueled by a Challenging Pinacol Coupling and Bicycle-forming Etherification
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The manginoids are a unique collection of bioactive natural products whose structures fuse an oxa-bridged spirocyclohexanedione with a heavily substituted trans-hydrindane framework. Herein, we show that such architectures can be accessed through a strategy combining a challenging pinacol coupling and bicycle-forming etherification with several additional chemo- and regioselective reactions. The success of these key events proved to be highly substrate and condition specific, affording insights for their application to other targets. As a result, not only has a 19-step total synthesis of manginoid A been achieved, but a potential roadmap to access other members of the family and related natural products has also been identified.
- Agarawal, Valay,Milkovits, Amanda,Snyder, Scott A.,Taylor, Cooper A.,Zhang, Yu-An
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- Tandem Diels-Alder and retro-ene reactions of 1-sulfenyl- and 1-sulfonyl-1,3-dienes as a traceless route to cyclohexenes
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A pericyclic approach for the synthesis of six-membered ring structures is described. The method employs 1,3-dienes with a 1-sulfur substituent in a tandem sequence of Diels-Alder and retro-ene reactions. In this pairing of [4 + 2] cycloaddition and 1,5-sigmatropic rearrangement, 1-sulfenyl-1,3-dienes engage in Diels-Alder reactions with electron-deficient dienophiles. Subsequently, the sulfenyl group of the cycloadducts is oxidized and unmasked to form allylic sulfinic acids, which undergo sterospecific reductive transposition via sulfur dioxide extrusion. The sequence can also include an inverse electron demand Diels-Alder reaction by using a 1-sulfonyl-1,3-diene. This combination of two pericyclic events offers novel stereocontrolled access to cyclohexenes that are inaccessible via a direct [4 + 2] cycloaddition route.
- Choi, Jin,Park, Hoyoon,Yoo, Hyun Jung,Kim, Sinae,Sorensen, Erik J.,Lee, Chulbom
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- Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF3) Aziridine and Cyclopropane Structures
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We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents in their α position were shown to undergo [2 + 1] annulations with vinyl ketones and tosyl-protected imines under mild reaction conditions.
- Delost, Michael D.,Njardarson, Jon T.
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supporting information
p. 6121 - 6125
(2021/08/16)
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- Rh-Catalyzed Annulation of Benzoic Acids, Formaldehyde, and Malonates via ortho-Hydroarylation to Indanones
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A three-component reaction from readily available low-cost materials of benzoic acids, formaldehyde, and malonates for the preparation of indanones by rhodium catalysis is reported. The annulation is initiated by an ortho-hydroarylation of benzoic acids, and a Lewis acid is not required. The solvent has a significant influence to the reaction, and 2-substituted or nonsubstituted indanones are obtained by the change of solvent.
- Yu, Shuling,Lv, Ningning,Hong, Chao,Liu, Zhanxiang,Zhang, Yuhong
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supporting information
p. 8354 - 8358
(2020/11/18)
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- Tandem Remote Csp3-H Activation/Csp3-Csp3 Cleavage in Unstrained Aliphatic Chains Assisted by Palladium(II)
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We report here a proof-of-concept for the cleavage of unstrained remote Csp3-Csp3 bonds at room temperature assisted by a directing group, opening up new possibilities to use aliphatic carboxylic acids as suitable alkenyl coupling partners. This strategy involves the Pd-mediated Csp3-H activation directed by a tethered 8-aminoquinoline group, followed by a concerted asynchronous carbene insertion into the Pd-C bond, and an unexpected β-carbon-carbon bond splitting. The insertion of a coupling partner into a Pd-C bond is a novel route to promote C-C bond cleavage, which in contrast to most common methodologies does not rely on the use of strained carbocycles.
- Pérez-Gómez, Marta,Azizollahi, Hamid,Franzoni, Ivan,Larin, Egor M.,Lautens, Mark,García-López, José-Antonio
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supporting information
p. 973 - 980
(2019/03/04)
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- Three-Dimensional Tetrathiafulvalene-Based Covalent Organic Frameworks for Tunable Electrical Conductivity
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The functionalization of three-dimensional (3D) covalent organic frameworks (COFs) is essential to broaden their applications. However, the introduction of organic groups with electroactive abilities into 3D COFs is still very limited. Herein we report the first case of 3D tetrathiafulvalene-based COFs (3D-TTF-COFs) with non- or 2-fold interpenetrated pts topology and tunable electrochemical activity. The obtained COFs show high crystallinity, permanent porosity, and large specific surface area (up to 3000 m2/g). Furthermore, these TTF-based COFs are redox active to form organic salts that exhibit tunable electric conductivity (as high as 1.4 × 10-2 S cm-1 at 120 °C) by iodine doping. These results open a way toward designing 3D electroactive COF materials and promote their applications in molecular electronics and energy storage.
- Chang, Jianhong,Fang, Qianrong,Guan, Xinyu,Li, Cuiyan,Li, Daohao,Li, Hui,Li, Shanshan,Qiu, Shilun,Tang, Lingxue,Valtchev, Valentin,Xue, Ming,Yan, Yushan
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supporting information
(2019/09/06)
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- A facile method for the synthesis of fused perhydropyrano[2,3: -b] pyrans promoted by Yb(OTf)3
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A stereospecific three-component domino reaction between glycals, alkylidene malonate and aldehydes catalyzed by Yb(OTf)3 is described. Multi-substituted cis-fused perhydropyrano[2,3-b]pyran derivatives were obtained with high diastereoselectiv
- Liang, Peng,Pan, Yang,Ma, Xiaofeng,Jiao, Wei,Shao, Huawu
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supporting information
p. 3763 - 3766
(2018/04/17)
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- Process for preparing 1,1-disubstituted ethylenic monomers
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The present invention relates to a process for preparing 1,1-disubstituted ethylene monomers having general formula (I) from a compound of general formula (II) and an active methylene compound of general formula (III) using a catalytic amount of an ammonium or iminium salt in homogeneous phase or supported on a solid substrate. Said process allows the direct synthesis of the monomers and finds application in the preparation of a wide variety of monomers. The products obtained are reactive monomers of high purity which find application in the field of fast curing adhesives.
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Paragraph 0092; 0106
(2015/11/16)
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- [4+2]-Annulations of aminocyclobutanes
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The first [4 + 2]-annulation between aminocyclobutanes and aldehydes to access tetrahydropyranyl amines is reported. With phthalimido cyclobutane dicarboxylates and aromatic aldehydes, tetrahydropyrans were obtained in 53-92% yield and 3:1-17:1 dr using scandium triflate or iron trichloride as catalyst. The use of thymine-or fluorouracil-substituted cyclobutanes gave direct access to six-membered ring nucleoside analogues. Finally, the [4 + 2]-annulation between aminocyclobutanes and enol ethers led to the corresponding cyclohexylamines.
- Waser, Jerome,Perrotta, Daniele,Racine, Sophie,Vuilleumier, Jeremy,De Nanteuil, Florian
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supporting information
p. 1030 - 1033
(2015/03/30)
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- Synthesis of aminocyclobutanes by iron-catalyzed [2+2] cycloaddition
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Fab Four: An iron-catalyzed [2+2] cycloaddition furnishes aminocyclobutanes with a broad range of substituents in excellent yields and diastereoselectivities. The products can be obtained on a gram scale and can be further converted to β-peptide derivatives in a few steps. Furthermore, a [4+2] cycloaddition between an aminocyclobutane and an olefin leads to the corresponding cyclohexylamines. Copyright
- De-Nanteuil, Florian,Waser, Jerome
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supporting information
p. 9009 - 9013
(2013/09/02)
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- Asymmetric total synthesis of an iboga-type indole alkaloid, voacangalactone, newly isolated from Voacanga africana
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A new hexacyclic iboga-type indole alkaloid, voacangalactone (1), was isolated from Voacanga africana, and its structure including the absolute configuration was established by asymmetric total synthesis involving such key steps as the asymmetric Diels-Alder reaction using an aminodiene and the construction of an isoquinuclidine ring and an indole skeleton.
- Harada, Masaya,Asaba, Ken Nunettsu,Iwai, Masumi,Kogure, Noriyuki,Kitajima, Mariko,Takayama, Hiromitsu
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supporting information
p. 5800 - 5803
(2013/01/15)
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- Synthesis of novel β-aminocyclobutanecarboxylic acid derivatives by a solvent-free aza-Michael addition and subsequent ring closure
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Novel β-aminocyclobutanecarboxylic acid derivatives were prepared via a sequential solvent-free aza-Michael addition of benzophenone imine across 3-halopropylidenemalonates and base-induced ring closure. These highly substituted cyclobutanedicarboxylic acid derivatives were subjected to a reactivity study which demonstrated the tendency of these donor-acceptor substituted four-membered rings to be converted into their corresponding ring-opened products.
- Meiresonne, Tamara,Mangelinckx, Sven,De Kimpe, Norbert
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supporting information; scheme or table
p. 7085 - 7091
(2011/11/04)
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- IMINIUM SALTS AND METHODS OF PREPARING ELECTRON DEFICIENT OLEFINS USING SUCH NOVEL IMINIUM SALTS
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This invention relates to novel iminium salts, which may be in the form of ionic liquids, and a process for producing electron deficient olefins, such as 2-cyanoacrylates, using such an iminium salt, for instance in the form of an ionic liquid.
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Page/Page column 39
(2008/12/05)
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- PREPARATION AND DIELS-ALDER REACTION OF N-CARBOMETHOXY-5-ETHYL-1,2-DIHYDROPYRIDINE: AN APPROACH FOR THE SYNTHESIS OF CATHARANTHINE
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N-carbomethoxy-5-ethyl-1,2-dihydropyridine (1) may be prepared by the bromination of N-carbomethoxy-3-ethyl-1,2,5,6-tetrahydropyridine (10), and subsequvent double dehydrobromination with EtAlCl2/HMPA; this diene undergoes Diels-Alder reaction with dimethyl methylenemalonate (2) to give the isoquinuclidine (3), an intermediate in our planned approach to catharanthine.
- Raucher, Stanley,Lawrence, Ross F.
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p. 2927 - 2930
(2007/10/02)
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- Process of preparing substituted acrylates
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Methylenemalonates are prepared by reacting a substituted norbornene with an electrophilic material in the presence of a lithium amide complex and pyrolyzing. The resulting acrylates are useful as fast setting, polymerizable adhesives.
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