- Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings
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A wide range of derivatives with new pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline skeleton was synthesized by free-radical intramolecular cyclization of o-bromophenyl-substituted pyrrolylpyridinium salts using the (TMS)3SiH/AIBN system. The cyclizat
- Khlebnikov, Alexander F.,Mosiagin, Ivan P.,Novikov, Mikhail S.,Spiridonova, Darya V.,Tomashenko, Olesya A.,Tunik, Sergey P.
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supporting information
p. 1490 - 1498
(2021/07/02)
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- Catalytic α-Selective Deuteration of Styrene Derivatives
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We report an operationally simple protocol for the catalytic α-deuteration of styrenes. This process proceeds via the base-catalyzed reversible addition of methanol to styrenes in DMSO-d6 solvent. The concentration of methanol is shown to be critical for high yields and selectivities over multiple competing side reactions. The synthetic utility of α-deuterated styrenes for accessing deuterium-labeled chiral benzylic stereocenters is demonstrated.
- Puleo, Thomas R.,Strong, Alivia J.,Bandar, Jeffrey S.
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supporting information
p. 1467 - 1472
(2019/01/25)
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- Weinreb Amide Directed Versatile C?H Bond Functionalization under (η5-Pentamethylcyclopentadienyl)cobalt(III) Catalysis
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The (η5-pentamethylcyclopentadienyl)cobalt(III) (Cp*CoIII)-catalyzed C?H bond functionalization of aromatic, heteroaromatic, and α,β-unsaturated Weinreb amides was explored. C?H allylation reactions with the use of allyl carbonate and a perfluoroalkene, oxidative alkenylation reactions with the use of ethyl acrylate, iodination reactions with the use of N-iodosuccinimide, and amidation reactions with the use of dioxazolones were catalyzed by Cp*Co(CO)I2 in the presence of a cationic Ag salt and AgOAc to afford various synthetically useful building blocks. Mechanistic studies of the C?H allylation disclosed that the C?H activation step was rate determining and virtually irreversible.
- Kawai, Kentaro,Bunno, Youka,Yoshino, Tatsuhiko,Matsunaga, Shigeki
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supporting information
p. 10231 - 10237
(2018/07/29)
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- Metathesis-active ligands enable a catalytic functional group metathesis between aroyl chlorides and aryl iodides
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Current methods for functional group interconversion have, for the most part, relied on relatively strong driving forces which often require highly reactive reagents to generate irreversibly a desired product in high yield and selectivity. These approaches generally prevent the use of the same catalytic strategy to perform the reverse reaction. Here we describe a catalytic functional group metathesis approach to interconvert, under CO-free conditions, two synthetically important classes of electrophiles that are often employed in the preparation of pharmaceuticals and agrochemicals—aroyl chlorides (ArCOCl) and aryl iodides (ArI). Our reaction design relies on the implementation of a key reversible ligand C–P bond cleavage event, which enables a non-innocent, metathesis-active phosphine ligand to mediate a rapid aryl group transfer between the two different electrophiles. Beyond enabling a practical and safer approach to the interconversion of ArCOCl and ArI, this type of ligand non-innocence provides a blueprint for the development of a broad range of functional group metathesis reactions employing synthetically relevant aryl electrophiles.
- Lee, Yong Ho,Morandi, Bill
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p. 1016 - 1022
(2018/09/06)
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- Diastereoselective C?H Bond Amination for Disubstituted Pyrrolidines
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We report herein the improved diastereoselective synthesis of 2,5-disubstituted pyrrolidines from aliphatic azides. Experimental and theoretical studies of the C?H amination reaction mediated by the iron dipyrrinato complex (AdL)FeCl(OEt2) provided a model for diastereoinduction and allowed for systematic variation of the catalyst to enhance selectivity. Among the iron alkoxide and aryloxide catalysts evaluated, the iron phenoxide complex exhibited superior performance towards the generation of syn 2,5-disubstituted pyrrolidines with high diastereoselectivity.
- Iovan, Diana A.,Wilding, Matthew J. T.,Baek, Yunjung,Hennessy, Elisabeth T.,Betley, Theodore A.
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supporting information
p. 15599 - 15602
(2017/11/16)
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- Wittig Reactions of Trialkylphosphine-derived Ylides: New Directions and Applications in Organic Synthesis
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The development of semi-stabilized, stabilized, and functionalized ylides derived from short-chain trialkylphosphines in the Wittig-type olefination reactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy separation of water-soluble phosphine oxides. The development of a mild organocatalytic process for the Wittig reaction and extension toward the preparation of reporter stilbenes under biological conditions are also described. Applications toward the preparation of biologically active natural products and derivatives are discussed.
- McNulty, James,McLeod, David,Das, Priyabrata,Zepeda-Velázquez, Carlos
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p. 619 - 632
(2016/01/15)
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- Lewis Acid Catalyzed Formal Intramolecular [3 + 3] Cross-Cycloaddition of Cyclopropane 1,1-Diesters for Construction of Benzobicyclo[2.2.2]octane Skeletons
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A novel Lewis acid catalyzed formal intramolecular [3 + 3] cross-cycloaddition (IMCC) of cyclopropane 1,1-diesters has been successfully developed. This supplies an efficient and conceptually new strategy for construction of bridged bicyclo[2.2.2]octane skeletons. This [3 + 3]IMCC could be run up to gram scale and from easily prepared starting materials. This [3 + 3]IMCC, together with our previously reported [3 + 2]IMCC strategy, can afford either the bicyclo[2.2.2]octane or bicyclo[3.2.1]octane skeletons from the similar starting materials by regulating the substituents on vinyl group.
- Ma, Weiwei,Fang, Jie,Ren, Jun,Wang, Zhongwen
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p. 4180 - 4183
(2015/09/15)
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- The ketene-surrogate coupling: Catalytic conversion of aryl iodides into aryl ketenes through ynol ethers
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tert-Butoxyacetylene is shown to undergo Sonogashira coupling with aryl iodides to yield aryl-substituted tert-butyl ynol ethers. These intermediates participate in a [1,5]-hydride shift, which results in the extrusion of isobutylene and the generation of aryl ketenes. The ketenes are trapped in situ with multiple nucleophiles or undergo electrocyclic ring closure to yield hydroxynaphthalenes and quinolines.
- Zhang, Wenhan,Ready, Joseph M.
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supporting information
p. 8980 - 8984
(2014/11/07)
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- An interesting competition between 6π-electro- and Garratt-Braverman cyclization in bis-diene-allene sulfones: Synergy between experiment and theory
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The reactivity of a series of bispropargyl sulfones with an ortho alkenyl moiety was studied. Under basic condition, these molecules isomerized to the bis-diene-allene system capable of undergoing 6π-electro-(EC) as well as Garratt-Braverman (GB) cyclizat
- Mondal, Sayantan,Basak, Amit,Jana, Saibal,Anoop, Anakuthil
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scheme or table
p. 7202 - 7210
(2012/08/29)
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- Copper-catalyzed recycling of halogen activating groups via 1,3-halogen migration
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A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp2 to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o-halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp3 C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.
- Grigg, R. David,Van Hoveln, Ryan,Schomaker, Jennifer M.
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supporting information
p. 16131 - 16134,4
(2020/09/09)
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- A direct synthesis of functionalized styrenes and terminal 1,3-dienes via aqueous Wittig chemistry with formalin
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A direct synthesis of functionalized styrenes including synthetically valuable styryl halides and terminal 1,3-dienes is reported directly from benzylic and allylic alcohols and aqueous formalin involving microwave assisted phosphonium salt formation and Wittig olefination under mildly basic conditions.
- Das, Priyabrata,McLeod, David,McNulty, James
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experimental part
p. 199 - 201
(2011/02/26)
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- Synthesis of indolines via a domino Cu-catalyzed amidation/cyclization reaction
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(Chemical Equation Presented) A highly efficient one-pot procedure for the synthesis of indolines and their homologues based on a domino Cu-catalyzed amidation/nucleophilic substitution reaction has been developed. Substituted 2-iodophenethyl mesylates and related compounds afforded the corresponding products in excellent yields. No erosion of optical purity was observed when transforming enantiomerically pure mesylates under the reaction conditions.
- Minatti, Ana,Buchwald, Stephen L.
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scheme or table
p. 2721 - 2724
(2009/05/27)
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- Selective functionalization of arenes through the reaction of aryne-zirconocene complexes and enol ethers
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A new method for the selective functionalization of aromatic rings by the zirconium promoted cross coupling reaction of an aryllithium compound and an enol ether is reported. Formation of an aryne-zirconocene complex and its regioselective coupling with a
- Barluenga, José,Fernández, Amadeo,álvarez-Rodrigo, Lucía,Rodríguez, Félix,Fa?anás, Francisco J.
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p. 2513 - 2515
(2007/10/03)
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- Synthesis of o-Dialkenylbenzenes and Indenes Using Heck and Oxypalladation Reactions
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o-Bromostyrenes 2-Br react with various alkenes in the presence of palladium catalysts to give either substituted indene 6 or o-diethenylbenzene derivatives 3, depending on the reaction conditions.Under oxidative conditions the latter can be cyclized to indene derivatives as well. - Keywords: Cross-coupling, Heck; Palladium catalysis; Indanes; Arenes, dialkenyl-N
- Braese, Stefan,Ruemper, Joerg,Voigt, Katharia,Albecq, Stephane,Thurau, Gert,et al.
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p. 671 - 678
(2007/10/03)
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- The Synthesis of Some Thiophenophanes and Attempted Cyclisations to Polycyclic Thiophenium Salts
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5,10-Diphenylcyclotrideca-2,4,10,12-tetraene-6,8-diyn-1-one (28), 5,6,7,8-tetrahydrodibenzocyclotridecen-15-one (21), and 13,14,16,17-tetrahydro-5,6,7,8-tetradehydrodibenzocyclotridecen-15-one (40) were synthesized.All attempts to add hydrogen sulphide across the triple bonds of these compounds to give thiophenes failed. 13,14,16,17-Tetrahydro-5,8-epithiodibenzocyclotridecen-15-one (43), from which hydrogen sulphide was removed by DDQ or chloroanil to give the ketone (40), was synthesized via the copper(II) acetate oxidation of 1,5-bis(2-ethynylphenyl)pentan-3-one (36).This ketone was obtained from 2-iodobenzaldehyde which on successive treatment with acetone, and ethynyltrimethylsilane yielded 1,5-bis(2-trimethylsilylethynylphenyl)penta-1,4-dien-3-one (18).Tributyltin hydride reduced the vinyl double bonds only in this ketone, and subsequent hydrolysis gave the ketone (36).Reduction of the cyclic ketone (40) with sodium borohydride gave the alcohol (41), sodium sulphide converted the diyne grouping into a thiophene ring giving the thiophene alcohol (42), and chromic acid now yielded the ketone (43).Attempts to convert this alcohol (42) and ketone (43) into pentacyclic sulphonium salts or related compounds resulted in elimination of oxygen and the formation of olefins.
- Acheson, R. Morrin,Lee, Gary C. M.
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p. 2321 - 2332
(2007/10/02)
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