- The Synthesis of Benzofulvenes through Palladium-Catalyzed Sequential Three-Component Reactions
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An approach for the synthesis of benzofulvenes has been developed through palladium-catalyzed sequential three-component reactions. The reactions likely involve C,C-palladacycles as the key intermediates. The palladacycles are generated through cascade reactions of aryl halides and alkynes, and then reacted with CH2Br2 to form benzofulvenes as the final products. (Figure presented.).
- Zhou, Bo,Wu, Zhuo,Qi, Weixin,Sun, Xueliang,Zhang, Yanghui
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p. 4480 - 4484
(2018/10/31)
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- Selective Divergent Synthesis of Indanols, Indanones, and Indenes via Acid-Mediated Cyclization of (Z)- and (E)-(2-Stilbenyl)methanols and Its Application for the Synthesis of Paucifloral F Derivatives
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Starting from bromo/iodobenzaldehyde derivatives, the corresponding (Z)- and (E)-(2-stilbenyl)methanols could be prepared in 2-5 steps via Pd-catalyzed cross-coupling reactions (Sonogashira and Heck reactions) followed by aryllithium/aryl Grignard addition. For the (E)-stilbenes, subsequent acid-mediated cyclization using p-TsOH immobilized on silica (PTS-Si) at low temperatures furnished the 2,3-trans-1-indanols with complete stereocontrol at the C2-C3. Further oxidization of the alcohol provided the indanones, which are structurally related to the natural product paucifloral F. At higher temperatures, 1,2- and 2,3-disubstituted indenes could be selectively prepared in good to excellent yields. On the other hand, the (Z)-stilbenes, under similar conditions (PTS-Si), did not give the indanols; only the 1,2-disubstituted indenes could be obtained. To gain further insights into the stereochemistry at C2-C3 for the (Z)-stilbenes, hydride or azide was employed as a nucleophile; the corresponding indane products were obtained with the cis stereochemistry at the C2-C3. Thus, the (Z)- or (E)-olefin geometry of the substrate directed the stereoselective indanyl cyclization to furnish the cis or trans at the C2-C3 ring junction, respectively, while reaction conditions controlled the selectivity of the product types.
- Jongcharoenkamol, Jira,Chuathong, Patsapon,Amako, Yuka,Kono, Masato,Poonswat, Kasam,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 13184 - 13210
(2018/11/02)
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- Intramolecular addition of triarylmethanes to alkynes promoted by KOtBu/DMF: A synthetic approach to indene derivatives
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A method for the intramolecular addition of triarylmethanes to alkynes has been developed. The reaction was efficiently promoted by KOtBu/DMF without any transition-metal catalyst. A variety of indene derivatives were prepared in moderate to good yields. A cascade cyclization of 2-alkyl-substituted substrates at elevated reaction temperature gave bicyclic indene derivatives. The reaction is proposed to proceed through the generation of a triphenylmethyl radical. Indene derivatives were prepared by the intramolecular addition of triarylmethanes to alkynes promoted by KOtBu/DMF. A cascade cyclization of 2-alkyl-substituted substrates at elevated reaction temperature gave bicyclic indene derivatives. A free-radical reaction mechanism is proposed.
- Chen, Yan-Yan,Chen, Zhen-Yu,Zhang, Niu-Niu,Chen, Jia-Hua,Zhang, Xue-Jing,Yan, Ming
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p. 599 - 606
(2016/02/19)
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- Palladium-catalyzed annulation of alkynes with ortho -halide-containing benzyl alcohols in aqueous medium
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The Pd-catalyzed annulations of ortho-halide-containing benzyl alcohols with alkynes for the synthesis of indenones were achieved in aqueous Triton X-100 micelles with good yields and wide substrate scopes. Moreover, the indenones obtained in this procedure can be further functionalized to form some more synthetic useful derivatives via an environmental-friendly way.
- Feng, Jie,Lu, Guoping,Lv, Meifang,Cai, Chun
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p. 10561 - 10567
(2015/02/19)
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- Synthesis of substituted 2-arylindanes from e -(2-stilbenyl)methanols via lewis acid-mediated cyclization and nucleophililc transfer from trialkylsilyl reagents
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A preparative method for the synthesis of functionalized 2-arylindanes has been developed via the Lewis acid-mediated ring closure of stilbenyl methanols followed by nucleophilic transfer from trialkylsilyl reagents. The reactions gave the corresponding p
- Sarnpitak, Pakornwit,Trongchit, Kanokrat,Kostenko, Yulia,Sathalalai, Supaporn,Gleeson, M. Paul,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 8281 - 8296
(2013/09/24)
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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
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2-Bromo-1-aryl substituted indenes can be synthesized from 1,2-diaryl substituted gem-dibromocyclopropanes via a domino reaction sequence. The cascade reaction involves silver(I) promoted ionization and 2π-disrotatory electrocyclic ring-opening, followed by a 4π-conrotatory electrocyclic ring closing reaction of the allylic carbocation intermediate. Reaction conditions utilize silver tetrafluoroborate (AgBF4) in dichloroethane at 65 C. Selectivity effects for the electrocyclization were also studied. The 2-bromoindenes can be further functionalized using cross-coupling reactions, such as the Suzuki-Miyaura protocol. The alkene π-bond of the indenes can also be isomerized to give the thermodynamically more stable 2-bromo-3-aryl-1H-indene isomers using triethylamine in dichloromethane at room temperature.
- Rosocha, Gregory,Batey, Robert A.
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p. 8758 - 8768
(2013/09/23)
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- 1,2,3,4-Tetrasubstituted cyclopentadienes and their applications for metallocenes: Efficient synthesis through zirconocene- and CuCl-mediated intermolecular coupling of two alkynes and one diiodomethane
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1,2,3,4-Tetrasubstituted cyclopentadienes and indene derivatives with identical or different substituents were obtained in good to excellent isolated yields through a zirconocene- and CuCl-mediated intermolecular coupling process. This synthetic procedure involved three organic partners, including one CH 2I2, and two different or identical alkynes. Two alkynes or one diyne undergo Cp2ZrII-mediated (Cp= η5-C5H5) pair-selective reductive coupling to afford the corresponding zirconacyclopentadiene derivatives, which react, in the presence of CuCl and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1 H)-pyrimidinone (DMPU), with CH2I2 through intermolecular followed by intramolecular coupling to afford the cyclopentadiene derivatives. An application of the prepared tetrasubstituted cyclopentadiene derivatives was demonstrated by the facile synthesis of the corresponding zirconocene complexes [(4RCp)2ZrCl2] and [(4RCp) 2ZrR′2] (R′=Me, Et, or nBu). The unique 1,2,3,4-tetrasubstituted cyclopentadiene ligands and the corresponding metallocenes are expected to have further applications in organometallic chemistry and organic synthesis. Ringing in the changes: A one-pot synthesis of 1,2,3,4-tetrasubstituted cyclopentadienes by zirconocene- and CuCl-mediated intermolecular coupling of two alkynes and diiodomethane (see scheme; Cp=η5-C5H5; DMPU=1,3-dimethyl-3,4,5,6- tetrahydro-2(1 H)-pyrimidinone) gave products that were successfully applied for the synthesis of the corresponding zirconocene derivatives. Copyright
- Geng, Weizhi,Wang, Chao,Guang, Jie,Hao, Wei,Zhang, Wen-Xiong,Xi, Zhenfeng
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p. 8657 - 8664
(2013/07/26)
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- Niobium-catalyzed activation of CF3 group on alkene: Synthesis of substituted indenes
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A CF3 group attached to an alkene functionality was activated by a zero-valent niobium catalyst to generate niobium alkenylcarbenoid species. The niobium carbenoid species then underwent insertion to an internal aromatic C-H σ bond to give inde
- Fuchibe, Kohei,Atobe, Kohei,Fujita, Yukari,Mori, Keiji,Akiyama, Takahiko
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supporting information; experimental part
p. 867 - 869
(2011/01/07)
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- Novel alkylidenating agents of iron(III) derivatives by base-mediated α,μ-dehydrohalogenation and their chemical trapping by cycloaddition
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Studies of the reactions between group 4 metal, chlorides (M = Ti, Zr, Hf) and methyllithium at -78 °C in toluene can lead to methylidene-metal complexes, H2C=MCl2, by a sequence of monomethylation, α-carbon lithiation and α,μ-elimination of LiCl. Here study of the preparation of alkylidene derivatives of iron was attempted by the interaction of FeCl3 with n-butyllithium in various ratios at -78 °C. The presence of any resulting butylidene-iron(III) derivative, nPrCH=FeE (E = Cl, nBu), was probed by adding chemical trapping agents, such as diphenylacetylene, benzonitrile, methyl benzoate and benzophenone. In each experiment the hydrolyzed products were consistent with a cycloaddition reaction of nPrCH=FeE with the trapping agent. The products from, di-phenylacetylene and from, benzonitrile with D2O workup are uniquely in accord with such a carbene precursor. A 3:1 ratio of nBuLi/FeCl3 gave the optimal yield of nPrCH=FenBu, ca. 80%, from, the MBu2FeCl precursor. When a 3:1. reaction mixture was simply brought to 25 °C and hydrolyzed, the purple alkylidene-iron complex decomposed completely to iron metal. A study of a 3:1 interaction of PhCH2MgCl and FeCl3 under similar conditions and trapping with diphenylacetylene provided evidence for the formation of PhCH=FeCH2Ph in ca. 40%. These results support; the hope that alkylidene-iron(III) analogs of the Grubbs reagents may be accessible by this process.
- Eisch, John J.,Sohn, Jane U.,Rabinowitz, Edon J.
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experimental part
p. 2971 - 2977
(2010/08/20)
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- Palladium-catalyzed double cross-coupling reaction of vic-diborylalkenes and -arenes with vic-bromo(bromomethyl)arenes
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Efficient annulation of vic-diborylalkenes and -arenes with vic-bromo(bromomethyl)arenes has been achieved, using Pd(PPh3) 4 as a catalyst in the presence of Cs2CO3 and water in THF at 60°C, giving rise to the c
- Shimizu, Masaki,Tomioka, Yosuke,Nagao, Ikuhiro,Hiyama, Tamejiro
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scheme or table
p. 3147 - 3150
(2010/03/24)
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- Rh(I)-catalyzed reaction of 2-(chloromethyl)phenylboronic acids and alkynes leading to indenes
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(Chemical Equation Presented) The reaction of 2-(chloromethyl)phenylboronic acid (1) with alkynes in the presence of a Rh(I) complex gave indene derivatives in high yields. The regioselectivity depends on the steric nature of the substituent on the alkynes. A bulky group favors the α-position of indenes.
- Miyamoto, Masaki,Harada, Yasuyuki,Tobisu, Mamoru,Chatani, Naoto
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supporting information; experimental part
p. 2975 - 2978
(2009/04/18)
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- Nickel-catalyzed carboannulation reaction of o-bromobenzyl zinc bromide with unsaturated compounds
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(Chemical Equation Presented) A number of indenes have been prepared in good yields by treating o-bromobenzyl zinc bromide 1 with various terminal and internal alkynes in the presence of a nickel catalyst. The nickel-catalyzed carboannulation reaction was successfully extended to the synthesis of indane derivatives by reaction of 1 with acrylates and styrene.
- Deng, Ruixue,Sun, Liangdong,Li, Zhi
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p. 5207 - 5210
(2008/09/17)
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- Dehydration of Alcohols Catalysed by Heteropolyacids Supported on Silica
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Keggin type heteropolyacids supported on silica efficiently dehydrate secondary and tertiary alcohols under mild conditions and in good yields to afford the correspondent alkenes.
- Alesso, Elba,Torviso, Rosario,Finkielsztein, Liliana,Lantano, Beatriz,Moltrasio, Graciela,Aguirre, Jose,Vazquez, Patricia,Pizzio, Luis,Caceres, Carmen,Blanco, Mirta,Thomas, Horacio
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p. 1232 - 1245
(2007/10/03)
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- Carbocyclic ring expansions with alkyne and carbene sources mediated by nickel(0) complexes: Structure of the critical organonickel intermediates
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Experimental evidence is assessed concerning the nature of organonickel intermediates involved in the cyclotrimerization and the cyclotetramerization of alkynes, as well as the cross-oligomerization of alkynes with carbene sources, as mediated by nickel(0) complexes. In the former processes a sequential series of nickelacycloalkapolyenes are the productive intermediates and in the latter cross-oligomerizations nickel(0)-carbene complexes themselves are critical precursors to the ultimately generated carbocycles.
- Eisch, John J.,Aradi, Allen A.,Lucarelli, Michael A.,Qian, Yun
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p. 1169 - 1184
(2007/10/03)
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- Metal-catalyzed cyclopropene rearrangements for benzannulation: Evaluation of an anthraquinone synthesis pathway and reevaluation of the parallel approach via carbene-chromium complexes
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The reaction of 3-arylcyclopropenes with Cr(CO)6 and Mo(CO)6 produces naphthols, in an example of metal-promoted benzannulation. Substituents at C- 3 (in addition to aryl) have a strong effect on the success of the process: 3-H deriv
- Semmelhack,Ho, Suzzy,Cohen,Steigerwald,Lee,Lee,Gilbert, Adam M.,Wutff, William D.,Ball, Richard G.
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p. 7108 - 7122
(2007/10/02)
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- Electrochemical Reduction of Activated Carbon-Carbon Double Bonds. Part 2. Mechanism and Stereochemistry of the Reduction of Self-protonating Indenes
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The reduction at a mercury electrode in dimethylformamide of five variously substituted indenes bearing at least one (acidic) hydrogen at C(1) was carried out, under self-protonation conditions and in the presence of phenol as a proton donor.Reduction occ
- Farnia, Giuseppe,Sandona, Giancarlo,Marcuzzi, Franco,Melloni, Giovanni
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p. 247 - 254
(2007/10/02)
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- SYNTHESIS OF INDENES FROM PHENYLPROPANONES USING ALUMINA CATALYST
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1,3-Diphenylpropan-2-one undergoes dehydration over alumina at around 400 deg C to form 1,3-diphenylallene which cyclizes to 2-phenylindene.Since the parent ketone can be obtained under the reaction conditions from phenylacetic acid, the present reaction forms a one step syntheses of 2-phenylindene from phenylacetic acid. 3- and 4-methylphenylacetic acids also give the corresponding indenes. 1,3-Diphenylpropan-1-ones also give phenylindenes, presumably by a direct cyclodehydration reaction.
- Jayamani, M.,Pant, Nalin,Ananthan, S.,Narayanan, K.,Pillai, C. N.
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p. 4325 - 4332
(2007/10/02)
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- Inter- versus Intramolecular Friedel-Crafts Reaction of Phenyl-substituted Dichlorocyclopropanes
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Friedel-Crafts reactions of the phenyl-substituted dichlorocyclopropanes 1-9 show different results.Thus, 1 (-> 10, 11), 3 (-> 12), 4(-> 13), 6 (-> 14), 8 (-> 15), and 9 (-> 16) yield indenes by the known intermolecular reaction with benzene.However, 2 (-
- Anke, Lutz,Weyerstahl, Peter
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p. 613 - 619
(2007/10/02)
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- The SRN1 Photoarylation of Indenyl Anions
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Irradiation of Me2SO solutions of indenyl anion and its phenylated analogues in the presence of bromobenzene produces the higher phenylated indenes.Thus indenyl anion (1b) yields 3-phenylindene (3a), 1-phenylindenyl anion (3b) yields 1,3- and 1,1-diphenylindene, 2-phenylindenyl anion (2b) produces 2,3-diphenylindene, 1,3-diphenylindenyl anion (6b) produces 1,1,3- and 1,2,3-triphenylindene, and 1,2-diphenylindenyl anion (5b) produces 1,2,3-triphenylindene (8).In liquid ammonia and tetrahydrofuran more complex reaction pathways are observed.The regiochemistry of phenylation is attributed to radical attack at the most basic site, in accord with a previously published model.
- Tolbert, Laren M.,Siddiqui, Shahabuddin
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p. 1744 - 1751
(2007/10/02)
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- CUMULENE PHOTOCHEMISTRY: PHENYL AND HYDROGEN MIGRATION IN PHENYLALLENE PHOTOREACTIONS
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Photoreactions of tetra- and triphenylallene and 1,3,3-triphenylcyclopropane in hydrocarbon solvents are reported.Intermediacy of vinylcarbenes is supported by independent generation experiments.
- Klett, Michael W.,Johnson, Richard P.
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p. 2523 - 2526
(2007/10/02)
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- THE EFFECTS OF THE NEIGHBORING METHOXYCARBONYL GROUP AND SULFUR ATOM(S) IN THE CARBON-SULFUR BOND CLEAVAGE AND THE ESTER EXCHANGE IN FLUORENE SYSTEMS
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9,9-bis(ethylthio)fluorene (1a) reacted with sodium ethanethiolate in methanol ro give 9-ethylthiofluorene and diethyl disulfide suggesting that a C-S bond cleavage occurs by attack of a nucleophile at sulfur if a leaving group is sufficiently stable.The pseudo-first-order rate constans for the reaction of 1a and methoxycarbonyl-substituted 9-ethylthiofluorenes have suggested that the methoxycarbonyl group at 1-position exerts through space interaction eith sulfur atoms(s).The rate constants for ester exchange in 1-methoxycarbonylfluorene and its derivatives have been discussed on the ground of neighboring sulfur participation.
- Nakanishi, Waro,Nakanishi, Hitoshi,Yanagawa, Yuko,Ikeda, Yoshitsugu,Oki, Michinori
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p. 105 - 108
(2007/10/02)
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- Sigmatropic Indenyl Rearrangements Induced by Electronic Excitation
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The photochemical rearrangement of several arylalkyl substituted indenes has been studied.The rearrangements were shown to be derived from the ?,?* singlet state since triplet sensitization led to no reaction or else resulted in a Paterno-Buchi
- Padwa, Albert,Goldstein, Steven,Loza, Roman,Pulwer, Mitchell
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p. 1858 - 1868
(2007/10/02)
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- Der konformative ortho-Effekt bei o-Tolylstilbenen und deren Vinyllithiumderivaten
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Geometrical isomers of stilbene derivatives with an additional, o-substituted phenyl moiety at the CC double bond (5, 6, 13) are prepared and structurally assigned.The isomer with the two phenyl groups in trans-position is favoured in equilibrium (conform
- Knorr, Rudolf,Lattke, Ernst,Raepple, Edith
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p. 1581 - 1591
(2007/10/02)
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