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Acid-Mediated Domino Cyclization of ortho-Formyl Cinnamate Esters: Synthesis of Substituted Indene/Indane Esters and Indeno[ a]indenones. J Org Chem 2024; 89:5069-5090. [PMID: 38497282 DOI: 10.1021/acs.joc.4c00301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
A Bro̷nsted acid-driven protocol to access substituted monoarylindene esters, biarylindane esters, and indeno[a]indenones from simple ortho-formylcinnamate esters and external arenes has been revealed. Remarkably, this single-pot process enabled the construction of two, three, and four new C-C bonds in building monoarylindene esters, biarylindane esters, and indeno[a]indenones, respectively, under metal-free and mild reaction parameters via triggering the inactive cinnamate ester moiety. In addition, the present strategy is investigated with widespread substrate scope.
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2
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Thermodynamics Evaluation of Selective Hydride Reduction for α,β-Unsaturated Carbonyl Compounds. Molecules 2023; 28:molecules28062862. [PMID: 36985834 PMCID: PMC10051270 DOI: 10.3390/molecules28062862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
The selective reduction of α,β-unsaturated carbonyl compounds is one of the core reactions and also a difficult task for organic synthesis. We have been attempting to study the thermodynamic data of these compounds to create a theoretical basis for organic synthesis and computational chemistry. By electrochemical measurement method and titration calorimetry, in acetonitrile at 298 K, the hydride affinity of two types of unsaturated bonds in α,β-unsaturated carbonyl compounds, their single-electron reduction potential, and the single-electron reduction potential of the corresponding radical intermediate are determined. Their hydrogen atom affinity, along with the hydrogen atom affinity and proton affinity of the corresponding radical anion, is also derived separately based on thermodynamic cycles. The above data are used to establish the corresponding "Molecule ID Card" (Molecule identity card) and analyze the reduction mechanism of unsaturated carbonyl compounds. Primarily, the mixture of any carbonyl hydride ions and Ac-tempo+ will stimulate hydride transfer process and create corresponding α,β-unsaturated carbonyl compounds and Ac-tempoH from a thermodynamic point of view.
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Dual Proton/Silver-Catalyzed Serial (5 + 2)-Cycloaddition and Nazarov Cyclization of ( E)-2-Arylidene-3-hydroxyindanones with Conjugated Eneynes: Synthesis of Indanone-Fused Benzo[ cd]azulenes. J Org Chem 2023; 88:3409-3423. [PMID: 36847758 DOI: 10.1021/acs.joc.2c02247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
A one-pot step-economic tandem process involving (5 + 2)-cycloaddition and Nazarov cyclization reactions has been reported for the facile synthesis of indanone-fused benzo[cd]azulenes from (E)-2-arylidene-3-hydroxyindanones and conjugated eneynes. This highly regio- and stereoselective bisannulation reaction is enabled by dual silver and Brønsted acid catalysis and opens up a new avenue for the construction of important bicyclo[5.3.0]decane skeletons.
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4
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The [3]Dendralene Motif as an Entry into Nazarov Cyclizations by Silylium-Ion Initiation. Org Lett 2023; 25:426-431. [PMID: 36603195 DOI: 10.1021/acs.orglett.2c04166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Geminal alkenes bearing an aryl and an allenyl group contain the motif of [3]dendralenes. The central alkene double bond in these cross-conjugated polyenes can be reacted with a silylium ion, thereby initiating a Nazarov cyclization. The cationic intermediate emerging from the electrocyclic ring closure is captured by hydride in the presence of excess hydrosilane. The resulting benzannulated methylenecyclopentene derivatives bearing a silylalkyl group then engage in silylium-ion regeneration followed by an unusual endo-selective intramolecular hydrosilylation. This cascade eventually leads to the formation of a silicon-containing bicyclo[3.2.1]octane skeleton.
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Preparation of 2,3-Dibromo-1 H-indenes and Tetrabromodihydro- s-indacenes as Synthetic Building Blocks. J Org Chem 2022; 87:13882-13890. [PMID: 36226725 DOI: 10.1021/acs.joc.2c01584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The acid-induced intramolecular cyclization of 1,1-disubstituted 3-aryl-2,3-dibromoallylalcohols affords 2,3-dibromo-1H-indene derivatives. This method is also applicable to the preparation of tetrabromodihydro-s-indacenes. The thus obtained multi-brominated compounds can serve as versatile synthetic building blocks to obtain a variety of indene and indacene derivatives, as demonstrated by the synthesis of dialkylmethylene-bridged oligo(phenylenevinylene)s, which feature attractive photophysical properties.
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Silylium-Ion-Promoted Hydrosilylation of Aryl-Substituted Allenes: Interception by Cyclization of the Allyl-Cation Intermediate. Org Lett 2022; 24:1346-1350. [PMID: 35113570 DOI: 10.1021/acs.orglett.2c00011] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A trityl-cation-initiated, silylium-ion-promoted hydrosilylation of aryl-substituted allenes is reported. Depending on the hydrosilane-to-initiator ratio, the hydrosilylation can be intercepted by an intramolecular electrophilic aromatic substitution or a Nazarov electrocyclization of an allyl-cation intermediate in the form of its endo isomer. By this, the selective formation of either the conventional 1,2-hydrosilylation product (vinylsilane) or a cyclized product (silylated indane) can be controlled.
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Pd-Catalyzed Nazarov-Type Cyclization: Application in the Total Synthesis of β-Diasarone and Other Complex Cyclopentanoids. Org Lett 2022; 24:1043-1048. [PMID: 35060746 DOI: 10.1021/acs.orglett.1c04243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the palladium-catalyzed Nazarov-type cyclization of easily accessible (hetero)arylallyl acetates to pentannulated (hetero)arenes. This method provides ready access to various types of bi-, tri-, tetra-, and pentacyclic cyclopentanoids under neutral conditions. The synthetic utility is further demonstrated in the first total synthesis of β-diasarone and several other complex cyclopentanoids relevant to medicinal chemistry and materials science.
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A Facile Approach to Access Multi‐Substituted Indenes via Nazarov Cyclisation of Aryl, Vinyl, and Alkyl/Aryl Carbinols. ChemistrySelect 2021. [DOI: 10.1002/slct.202103141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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9
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α‐Substituted Chalcones: A Key Review. ChemistrySelect 2021. [DOI: 10.1002/slct.202103325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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TfOH catalysed domino-double annulation of arenes with propargylic alcohols: a unified approach to indene polycyclic systems. Chem Commun (Camb) 2021; 57:12796-12799. [PMID: 34782905 DOI: 10.1039/d1cc05253e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design and development of a TfOH catalysed domino strategy for the double annulation of arenes with propargylic alcohols for the rapid generation of indene based polycyclic systems is reported. The dehydration, intramolecular 6-endo-dig hydroarylation, and cationic cyclization were consecutively promoted by TfOH. The key features of this strategy are the formation of two C-C bonds, unified access to indene polycyclic systems, excellent yields (up to 95%), high atom economy (>90%), an operationally simple procedure, and water being the only byproduct. By extending this strategy, a two-step synthesis of the pentacyclic systems of hypoxylonol A (43% overall yield from α-tetralone), daldinone A (63% overall yield from β-tetralone) and spiro-tetracyclic framework of incarviatone A has also been achieved.
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11
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Sequential Knoevenagel Condensation/Cyclization for the Synthesis of Indene and Benzofulvene Derivatives. ACS OMEGA 2021; 6:28441-28454. [PMID: 34723041 PMCID: PMC8552470 DOI: 10.1021/acsomega.1c05283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Sequential Knoevenagel condensation/cyclization leading to indene and benzofulvene derivatives has been developed. The reaction of 2-(1-phenylvinyl)benzaldehyde with malonates gave benzylidene malonates, cyclized indenes, and dehydrogenated benzofulvenes. The product selectivity depends on the reaction conditions. The reaction with piperidine, AcOH in benzene at 80 °C for 1.5 h gave a benzylidene malonate in 75% yield as a major product. The reactions with piperidine, AcOH in benzene at 80 °C for 17 h and with TiCl4-pyridine at room temperature gave an indene derivative in 56 and 79% yields, respectively, as a major product. The reaction with TiCl4-Et3N gave a benzofulvene in 40% yield selectively. Indene was transformed to a benzofulvene derivative using the reagents TiCl4-Et3N and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The reaction of variously substituted aryl derivatives with dimethyl malonate gave indene and benzofulvene derivatives. The reactions of 2-(1-phenylvinyl)benzaldehyde with Meldrum's acid or malononitrile also gave cyclized compounds in the suitable sequential or stepwise conditions. Furthermore, the reaction of 2-arylbenzaldehydes has been investigated. The limitation and scope have been described. The reaction mechanism of the cyclization steps has been examined by DFT calculations.
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12
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Stereoselective synthesis of 9-vinyl substituted unsymmetrical xanthenes and thioxanthenes. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Synthesis of 11-aryl-11H-indeno[1′,2′:4,5]imidazo[1,2-a]pyridines via dehydrative cyclization of aryl(2-arylimidazo[1,2-a]pyridin-3-yl)methanols. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.06.068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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14
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15
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16
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Leveraging the Halo-Nazarov Cyclization for the Chemodivergent Assembly of Functionalized Haloindenes and Indanones. J Am Chem Soc 2019; 141:5461-5469. [DOI: 10.1021/jacs.9b00198] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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17
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Synthesis and evaluation of novel α-substituted chalcones with potent anti-cancer activities and ability to overcome multidrug resistance. Bioorg Chem 2019; 87:123-135. [PMID: 30884306 DOI: 10.1016/j.bioorg.2019.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/24/2019] [Accepted: 03/06/2019] [Indexed: 02/06/2023]
Abstract
A series of forty α-substituted chalcones were synthesized and screened for their antiproliferative activities against HCT116 (colorectal) and HCC1954 (breast) cancer cell lines. Compounds 5a and 5e were found to be the most potent compounds with GI50 values of 0.63 µM and 0.725 µM in HCC1954 cell line and 0.69 µM and 1.59 µM in HCT116 cell line, respectively. Both compounds induced a G2/M cell cycle arrest and caused apoptotic cell death in HCT116 cells as shown by the induction of PARP cleavage. The compounds also stabilized p53 in a dose-dependent manner in HCT116 cells following 24-hour treatment. Furthermore, both 5a and 5e were able to overcome multidrug resistance in two MDR-1 overexpressing multidrug resistant cell lines.
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18
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Cationic Cascade for Building Complex Polycyclic Molecules from Simple Precursors: Diastereoselective Installation of Three Contiguous Stereogenic Centers in a One-Pot Process. J Am Chem Soc 2018; 141:118-122. [DOI: 10.1021/jacs.8b11713] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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N-Silylenamines as Reactive Intermediates: Hydroamination for the Modular Synthesis of Selectively Substituted Pyridines. Org Lett 2018; 20:6663-6667. [PMID: 30351966 DOI: 10.1021/acs.orglett.8b02703] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A modular and selective synthesis of mono-, di-, tri-, tetra-, and pentasubstituted pyridines is reported. Hydroamination of alkynes with N-silylamine using a bis(amidate)bis(amido)titanium(IV) precatalyst furnishes the regioselective formation of N-silylenamines. Addition of α,β-unsaturated carbonyls to the crude mixtures followed by oxidation affords 47 examples of pyridines in yields of up to 96%. This synthetic route allows for the synthesis of diverse pyridines containing variable substitution patterns, including pharmaceutically relevant 2,4,5-trisubstituted pyridines, using this one-pot protocol.
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Facile Synthesis of 3-Arylindenes by HMPA-Promoted Direct Arylation of Indenes with Aryl Fluorides. ACS OMEGA 2018; 3:10099-10106. [PMID: 31459139 PMCID: PMC6645374 DOI: 10.1021/acsomega.8b01542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/02/2018] [Indexed: 06/10/2023]
Abstract
A rapid and efficient approach to 3-arylated indenes by reactions of indenes with unactivated fluoroarenes with the assistance of lithium diisopropylamide and hexamethylphosphoramide at room temperature was developed.
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21
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Chiral Brønsted Acid Catalyzed Enantioselective Dehydrative Nazarov-Type Electrocyclization of Aryl and 2-Thienyl Vinyl Alcohols. J Am Chem Soc 2018; 140:5834-5841. [PMID: 29631393 DOI: 10.1021/jacs.8b02339] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An efficient chiral Brønsted acid-catalyzed enantioselective dehydrative Nazarov-type electrocyclization (DNE) of electron-rich aryl- and 2-thienyl-β-amino-2-en-1-ols is described. The 4π conrotatory electrocyclization reaction affords access to a wide variety of the corresponding 1 H-indenes and 4 H-cyclopenta[ b]thiophenes in excellent yields of up to 99% and enantiomeric excess (ee) values of up to 99%. Experimental and computational studies based on a proposed intimate contact ion-pair species that is further assisted by hydrogen bonding between the amino group of the substrate cation and chiral catalyst anion provide insight into the observed product enantioselectivities.
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22
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Microwave‐Assisted, Asymmetric Synthesis of 3‐Amino‐2,3‐Dihydrobenzofuran Flavonoid Derivatives from Chalcones. Chemistry 2018; 24:4509-4514. [PMID: 29446184 DOI: 10.1002/chem.201705984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Indexed: 01/25/2023]
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23
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Synthesis of Indenes that are Derived from Aldimines with Enones Under Rhodium(III) Catalysis. ASIAN J ORG CHEM 2017. [DOI: 10.1002/ajoc.201700473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Enzymatic Tandem Approach to Knoevenagel Condensation of Acetaldehyde with Acidic Methylene Compounds in Organic Media. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700936] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Dehydrative Nazarov-type electrocyclizations of alkenyl (hetero)aryl carbinols via calcium catalysis: Access to cyclopenta[b]thiophenes and indene derivatives. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.03.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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26
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Synthesis of Selectively Substituted or Deuterated Indenes via Sequential Pd and Ru Catalysis. J Org Chem 2017; 82:4226-4234. [DOI: 10.1021/acs.joc.7b00200] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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27
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Acid-promoted cyclization of 2,4-diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers into CF3-indenes. Org Biomol Chem 2017; 15:2541-2550. [DOI: 10.1039/c7ob00406k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
2,4-Diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers in H2SO4 at room temperature in just 2 min are quantitatively cyclized into 1-aryl-3-trifluoromethyl-1H-indenes.
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28
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Catalytic Rearrangement of 2-Alkoxy Diallyl Alcohols: Access to Polysubstituted Cyclopentenones. Org Lett 2016; 18:1326-9. [DOI: 10.1021/acs.orglett.6b00270] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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One-pot relay catalysis: divergent synthesis of furo[3,4-b]indoles and cyclopenta[b]indoles from 3-(2-aminophenyl)-1,4-enynols. Org Biomol Chem 2016; 14:5563-8. [DOI: 10.1039/c6ob00319b] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Described herein a divergent strategy for the synthesis of furo[3,4-b]indoles via a sequential Ag(i)/Bi(iii)/Pd(ii) catalysis and cyclopenta[b]indoles via a one-pot Ag(i)/Brønsted acid relay catalysis, starting from the easily accessible 3-(2 aminophenyl)-4-pentenyn-3-ols.
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31
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Synthesis and Halogen Bonding in the Crystal Structures of the New 2,3-Diiodo Indenone and 1-Ethoxy-2,3-diiodo Indene. HETEROATOM CHEMISTRY 2015. [DOI: 10.1002/hc.21303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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32
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Synthesis and Acid-Catalyzed Cyclization of 2-Alkenylstilbenes: a New Approach to the Substituted Indenes. CHINESE J CHEM 2015. [DOI: 10.1002/cjoc.201500587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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A Tin(IV) Chloride Promoted Tandem C-O Bond Cleavage/Nazarov Cyclization/Nucleophilic Addition Reaction of 1,1-Disubstituted Allylic Ethers toward the Synthesis of Multisubstituted Indenes. Org Lett 2015; 17:5288-91. [PMID: 26465205 DOI: 10.1021/acs.orglett.5b02610] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A novel SnCl4-promoted tandem reaction toward multisubstituted indenes via a sequential C-O bond cleavage/Nazarov cyclization/nucleophilic addition reaction has been developed to afford a series of multisubstituted indenes with an all-carbon quaternary center in moderate to good yields.
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Nazarov Cyclization of Divinyl and Arylvinyl Epoxides: Application in the Synthesis of Resveratrol-Based Natural Products. Chemistry 2015; 21:6475-80. [DOI: 10.1002/chem.201500362] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Indexed: 11/05/2022]
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35
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The synthesis of 1,2-diarylindenes via DDQ-mediated dehydrogenative intramolecular cyclization. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.05.088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Synthesis of highly substituted indene derivatives by Brønsted acid catalyzed Friedel–Crafts reaction of homoallylic alcohols. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.05.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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37
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Synthesis and antiproliferative activity of α-branched α,β-unsaturated ketones. Eur J Med Chem 2013; 70:568-78. [PMID: 24211632 DOI: 10.1016/j.ejmech.2013.10.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/27/2013] [Accepted: 10/13/2013] [Indexed: 10/26/2022]
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38
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Drawing from a Pool of Radicals for the Design of Selective Enyne Cyclizations. Org Lett 2013; 15:5650-3. [DOI: 10.1021/ol4028072] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Synthesis of 2-bromo-1-aryl-1H-indenes via a Ag(I) promoted domino 2π-electrocyclic ring-opening/4π-electrocyclization reaction of 1,2-diaryl substituted gem-dibromocyclopropanes. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.07.086] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Opening or closing the lock? When reactivity is the key to biological activity. Chemistry 2013; 19:15384-95. [PMID: 24105896 DOI: 10.1002/chem.201302117] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Indexed: 12/14/2022]
Abstract
Thiol-mediated processes play a key role to induce or inhibit inflammation proteins. Tailoring the reactivity of electrophiles can enhance the selectivity to address only certain surface cysteines. Fourteen 2',3,4,4'-tetramethoxychalcones with different α-X substituents (X=H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) were synthesized, containing the potentially electrophilic α,β-unsaturated carbonyl unit. The assessment of their reactivity as electrophiles in thia-Michael additions with cysteamine shows a change in the reactivity of more than six orders of magnitude. Moreover, a clear correlation between their reactivity and an influence on the inflammation proteins heme oxygenase-1 (HO-1) and the inducible NO synthase (iNOS) is demonstrated. As the biologically most active compound, the α-CF3 -chalcone is shown to inhibit the NO production in RAW264.7 mouse macrophages in the nanomolar range.
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41
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42
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FeCl3 mediated intramolecular olefin-cation cyclization of cinnamates for the synthesis of highly substituted indenes. Chem Commun (Camb) 2013; 49:8051-3. [DOI: 10.1039/c3cc43159b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Mild boronic acid catalyzed Nazarov cyclization of divinyl alcohols in tandem with Diels–Alder cycloaddition. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2012.10.100] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Synthesis of Indenes via Brønsted Acid Catalyzed Cyclization of Diaryl- and Alkyl Aryl-1,3-dienes. Org Lett 2012; 14:5392-5. [DOI: 10.1021/ol302271w] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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45
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Gold(I)-Catalyzed Cyclodehydration Enabled by the Triisopropylsilyl Group: A Synthetically Versatile Methodology. Helv Chim Acta 2012. [DOI: 10.1002/hlca.201200176] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
46
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One-Pot Organocatalytic Tandem Aldol/Polycyclization Reactions between 1,3-Dicarbonyl Compounds and α,β,γ,δ-Unsaturated Aldehydes for the Straightforward Assembly of Cyclopenta[b]furan-Type Derivatives: New Insight into the Knoevenagel Reaction. Chemistry 2012; 18:2382-8. [DOI: 10.1002/chem.201103080] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Indexed: 11/11/2022]
|
47
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Ferric chloride-catalyzed C–N bond cleavage for the cyclization of arylallenes leading to polysubstituted indenes. Chem Commun (Camb) 2012; 48:10913-5. [DOI: 10.1039/c2cc36048a] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
48
|
Formation of Five- and Seven-Membered Rings Enabled by the Triisopropylsilyl Auxiliary Group. Org Lett 2011; 14:414-7. [DOI: 10.1021/ol203209b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
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Addition of Arylboronic Acids to Arylpropargyl Alcohols en Route to Indenes and Quinolines. Org Lett 2011; 13:5314-7. [DOI: 10.1021/ol202176g] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Palladium-Catalyzed Oxidative Rearrangement of Diaryl Alkenyl Carbinols to β,β-Diaryl α,β-Unsaturated Ketones. Org Lett 2011; 13:3648-51. [DOI: 10.1021/ol201177t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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