- Palladium catalysed reactions of allene with active methylene pronucleophiles. C-1,3-Dienylmethyl derivatives and their Diels-Alder reactions
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A 2-step 100% atom economic sequence is reported whereby active methylene pronucleophiles react with 2 mol equiv. of allene to give bis-1,3-dienylmethyl derivatives of the pronucleophiles. Subsequent double Diels-Alder reactions furnish 1,1′-linked cyclohexenes with a 3-carbon spacer.
- Grigg, Ronald,Kongathip, Ngampong,Kongathip, Boonsang,Luangkamin, Suwaporn,Dondas, H.Ali
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Read Online
- Silica Support-Enhanced Pd-Catalyzed Allylation Using Allylic Alcohols
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Although allylation using allylic alcohol is an environmentally-friendly method because of water being the sole byproduct in such reactions, allylic alcohol is one of the most difficult allylating agents in Pd-catalyzed allylation of nucleophiles. In this study, we successfully developed a mesoporous silica-supported Pd complex as an efficient catalyst for the allylation of nucleophiles using allylic alcohols as allylating agents. The allylic alcohol is activated by the silanol group on the support surface, which easily undergoes a π-allylpalladium intermediate formation. The catalytic activity of the supported Pd complex was ca. 9 times higher than that of its homogeneous precursor Pd complex. A highest turnover number of 4500 based on Pd was achieved. Various nucleophiles and allylic alcohol derivatives could be used as substrates. Not only the detailed catalyst structure but also the reaction mechanism including the concerted activation of allylic alcohol by the Pd complex and silanol were investigated by several spectroscopic techniques, such as Pd K-edge XAFS, solid-state NMR, and in-situ FT-IR measurements.
- Motokura, Ken,Ikeda, Marika,Kim, Minjune,Nakajima, Kiyotaka,Kawashima, Sae,Nambo, Masayuki,Chun, Wang-Jae,Tanaka, Shinji
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p. 4536 - 4544
(2018/09/21)
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- MMZNiY-Catalyzed Tsuji–Trost Type of Reaction: A Selective Mono/Bis Allylation of Dicarbonyl Compounds
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Abstract: An alternative method to Pd-catalyzed Tsuji–Trost reaction is developed and it provides a simpler route for the selective synthesis of a broad range of mono-/bis-allylated and cinnamylated 1,3-dicarbonyl compounds using MMZNiY catalyst at room temperature. Product selectivity can be controlled by the proper choice of catalyst. The catalyst was also well characterized by SEM, TEM, HRTEM, EDAX and X-ray analysis. Other advantages of catalyst like its ease of preparation, functional tolerance and its reusability are also highlighted.
- Senthilkumar, Samuthirarajan,Thangapriya, Cheirmakani,Alagumurugayee, Raman,Kumarraja, Mayilvasagam
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p. 2755 - 2763
(2017/09/14)
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- Nickel-Catalysed Bis-Allylation of Activated Nucleophiles with Allyl Alcohol
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Nickel-based catalysis allows the efficient bis-allylation of soft nucleophiles with allylic alcohols. The reaction is best promoted by a combination of Ni(cod)2 (cod = cyclooctadienyl) and diphenylphosphinobutane under additive-free conditions. Alternatively, nickel(II) precursors can be used provided that a reductant is used to generate the nickel(0) species. The NiCl2/Zn combination is particularly simple, and can advantageously replace the use of the more air-sensitive Ni(cod)2 precursor. The scope of the reaction was studied with nucleophiles and allylic derivatives suitable for bis-allylation reactions.
- Blieck, Rémi,Azizi, Mohamed Salah,Mifleur, Alexis,Roger, Maxime,Persyn, Clément,Sauthier, Mathieu,Bonin, Hélène
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p. 1194 - 1198
(2016/03/05)
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- Diversity-oriented approach to spirocycles with indole moiety via Fischer indole cyclization, olefin metathesis and Suzuki-Miyaura cross-coupling reactions
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A range of aryl substituted spirocycles containing the indole moiety have been assembled through Claisen rearrangement, Fischer indole cyclization, ring-closing metathesis and the Suzuki-Miyaura cross-coupling reactions. Some of these molecules contain ei
- Kotha, Sambasivarao,Ali, Rashid,Srinivas, Venu,Krishna, Nimita G.
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p. 129 - 138
(2015/01/09)
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- Palladium nanoparticles bonded to two-dimensional iron oxide graphene nanosheets: A synergistic and highly reusable catalyst for the Tsuji-Trost reaction in water and air
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Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst- catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe3O4 and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe3O4 nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe3O4/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99% isolated yield, and the turnover frequency reached 2200 h-1. The yield of allylated products was 66% for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5% of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment. Picking up speed: A multifunctional Pd nanocatalyst was synthesized by in situ growth of palladium nanoparticles (PdNPs) and the assembly of Fe3O4 NPs on reduced graphene oxide (rGO) by employing polyethyleneimine as the coupling linker. This nanocatalyst exhibits synergistic catalysis by the amine on the same rGO surface as the PdNPs for acceleration of the Tsuji-Trost reaction in water and air (see figure).
- Liu, Jian,Huo, Xing,Li, Tianrong,Yang, Zhengyin,Xi, Pinxian,Wang, Zhiyi,Wang, Baodui
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p. 11549 - 11555
(2014/11/07)
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- Efficient allylation of nucleophiles catalyzed by a bifunctional heterogeneous palladium complex-tertiary amine system
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We demonstrate the synergistic catalysis of a silica-supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/ NEt2) as well as synthetic scope of the Tsuji-Trost reaction of 1,3-dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt 2 exhibited wide applicability and high activity for the Tsuji-Trost reaction. For example, the reaction of ethyl 3-oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 °C for 5 h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0 mmol of ethyl 3-oxobutanate using 0.60 μmol of Pd in SiO2/diamine/Pd/NEt 2, the turnover number (TON) of Pd reached up to 1070 within 24 h. Phenols with electron-withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/ Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p-chlorophenol. Copyright
- Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
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p. 973 - 980
(2013/05/08)
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- Ruthenium catalyzed selective regio-and-mono-allylation of cyclic 1,3-diketones using allyl alcohols as substrates
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The new ruthenium-sulfonate catalyst Ru(Cp*) (η3-C3H5)(p-CH3C 6H4SO3)2, (Cp*= pentamethylcyclopentadienyl), rapidly and regioselectively mono-all
- Gruber, Stefan,Pregosin, Paul S.
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experimental part
p. 3235 - 3242
(2010/04/28)
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- Solvent-controlled highly selective bis-and monoallylation of active methylene compounds by allyl acetate with palladium(0) nanoparticle
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(Chemical Equation Presented) Palladium(0) nanoparticle has been used as an efficient catalyst for the allylation of active methylene compounds. Very efficient bisallylation is achieved for a variety of active methylene compounds by allyl acetate and its derivatives in one stroke in THF solvent. The reaction in water provides monoallylated product selectively by allyl acetate only. The recovered Pd(0) nanoparticle is recycled. A probable mechanism is suggested.
- Ranu, Brindaban C.,Chattopadhyay, Kalicharan,Adak, Laksmikanta
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p. 4595 - 4598
(2008/03/12)
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- Montmorillonite-entrapped sub-nanoordered Pd clusters as a heterogeneous catalyst for allylic substitution reactions
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(Chemical Equation Presented) Caught making a change: Stable sub-nanoordered Pd clusters within the interlayer spaces of montmorillonite efficiently catalyze heterogeneous allylic substitution reactions in which the coordinatively unsaturated Pd atoms enable facile formation of π-allylpalladium intermediates (see scheme). The catalyst is reusable without any loss of activity or selectivity.
- Mitsudome, Takato,Nose, Kenta,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 3288 - 3290
(2008/03/11)
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- Water enables direct use of allyl alcohol for Tsuji-Trost reaction without activators
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(Chemical Equation Presented) An aqueous biphasic reaction system enables the direct use of allyl alcohol in the Tsuji-Trost reaction without the help of any activating reagents for allyl alcohol. The reaction conditions are neutral to basic, allowing the use of amines as the nucleophile. Theoretical calculations have elucidated the importance of hydration of the hydroxy group for the smooth generation of π-allylpalladium species.
- Kinoshita, Hidenori,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 4085 - 4088
(2007/10/03)
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- Solid-supported cyclohexane-1,3-dione (CHD): A "capture and release" reagent for the synthesis of amides and novel scavenger resin
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A three-step synthesis of cyclohexane-1,3-dione (CHD) resin 6 on polystyrene resin is described. Resin 6 was used to prepare an amide library of high purity by microwave-assisted serial "capture and release" and can be recycled for this purpose. High-loading CHD resin 10 was also shown to scavenge allyl cations in solution.
- Humphrey, Cara E.,Easson, Morag A. M.,Tierney, Jason P.,Turner, Nicholas J.
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p. 849 - 852
(2007/10/03)
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- Spiro-annulation via ring closing metathesis reaction
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Various spiro cyclic systems are prepared from β-di-carbonyl compounds and active methylene substrates via palladium catalyzed allylation and ring- closing metathesis (RCM) reaction as key steps.
- Kotha, Sambasivarao,Manivannan, Ethirajan,Ganesh, Thota,Sreenivasachary, Nampally,Deb, Ashoke
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p. 1618 - 1620
(2007/10/03)
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- C-ALLYLATION OF CYCLIC β-DIKETONES IN AN ACIDIC MEDIUM WITH CATALYSIS BY Pd(0)
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A method is proposed for the C-alkylation of cyclic β-diketones by allyl acetate in a weakly acidic medium with Pd(PPh3)4 as catalyst.The method makes it possible to obtain high yields of the corresponding mono- and diallylated products.
- Lapitskaya, M. A.,Pivnitskii, K. K.
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p. 1665 - 1668
(2007/10/02)
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- Palladium- and Rhodium-catalysed Cyclisation of 1,6-, 1,7- and 1,8-Dienes to Cyclopentenes and Methylenecyclopentenes. Crystal Structure of Dichloro(4,4-diacetylhepta-1,6-diene)platinum(II)
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Hepta-1,6-dienes disubstituted at C-4 with certain carbonyl-containing groups cyclise, in good yield, to the corresponding 4,4-disubstituted 1,2-dimethylcyclopent-2-enes when treated with a catalytic amount of palladium acetate in chloroform containing hydrogen chloride.Changing the catalyst precursor to chlorotris(triphenylphosphine)rhodium(I) led to the formation of the corresponding 1-methyl-2-methylenecyclopentanes which, in turn, isomerised to 1,2-dimethylcyclopent-1-enes in ethanolic hydrogen chloride containing the rhodium complex.The effect of terminal substitution of the dienes with methyl groups was examined. 1,7- and 1,8-Dienes give rise to mixtures of five-membered ring products.Possible mechanisms for the catalytic processes are discussed.The X-ray crystal structure analysis of dichloro(4,4-diacetylhepta-1,6-diene)platinum(II) is reported.
- Grigg, Ronald,Malone, John F.,Mitchell, Thomas R. B.,Ramasubbu, Asnok,Scott, Ronald M.
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p. 1745 - 1754
(2007/10/02)
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