- Concerted Catalysis in Tight Spaces: Palladium-Catalyzed Allylation Reactions Accelerated by Accumulated Active Sites in Mesoporous Silica
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The surface of mesoporous silica was modified with a Pd–bisphosphine complex and/or a tertiary amine group for concerted acceleration of allylation reactions. Mesoporous-silica-supported catalysts with a 1.6 nm pore diameter showed higher performance than nonporous or larger mesoporous silica-supported catalysts owing to the accumulation of active sites into a confined space. For the case in which allyl alcohol was used in the reaction, the presence of a silanol group on the surface was quite effective: the turnover number of Pd was nine times greater than that of the homogeneous Pd complex.
- Motokura, Ken,Ikeda, Marika,Nambo, Masayuki,Chun, Wang-Jae,Nakajima, Kiyotaka,Tanaka, Shinji
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- Co-immobilization of a palladium-bisphosphine complex and strong organic base on a silica surface for heterogeneous synergistic catalysis
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Co-immobilization of a palladium-bisphosphine complex and a strong organic base, 1,4-diazabicyclo[2.2.2]octane (DABCO), on a silica support was successfully achieved. The new catalyst structure was characterized by X-ray photoelectron spectroscopy, solid-
- Motokura, Ken,Saitoh, Koki,Noda, Hiroto,Uemura, Yohei,Chun, Wang-Jae,Miyaji, Akimitsu,Yamaguchi, Sho,Baba, Toshihide
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- Heterogeneous synergistic catalysis by a palladium complex and an amine on a silica surface for acceleration of the Tsuji-Trost reaction
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The cooperative surface-catalysis strategy of a Bronsted acid and an organic base can be extended to a metal complex and organic base pair. A silica-supported diaminopalladium complex and a tertiary amine were prepared and characterized. The Pd-catalyzed
- Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
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- Combining palladium complex and organic amine on graphene oxide for promoted Tsuji-Trost allylation
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In this study, we develop a facile strategy to combine an organic amine with a palladium complex on graphene oxide (GO) as a cooperative catalyst for Tsuji-Trost allylation. A tertiary amine and palladium-diamine complex are simultaneously immobilized on
- Zhao, Qingshan,Zhu, Yuanzhi,Sun, Zhen,Li, Yang,Zhang, Guoliang,Zhang, Fengbao,Fan, Xiaobin
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- Accumulation of Active Species in Silica Mesopore: Effect of the Pore Size and Free Base Additives on Pd-catalyzed Allylation using Allylic Alcohol
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A mesoporous silica-supported Pd complex was prepared using various types of porous silica supports (pore size: 16–31 ?). The effects of the pore size and base additive properties on the catalytic allylation were investigated. The activity of the Pd-catal
- Chun, Wang-Jae,Kawashima, Sae,Manaka, Yuichi,Motokura, Ken,Nambo, Masayuki
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- The asymmetric synthesis of cyclopentane derivatives by palladium- catalyzed coupling of prochiral alkylboron compounds
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Treatment of the prochiral triflate 2a with Pd2(dba)3·CHCl3, (S)- (R)-BPPFOAc and K2CO3, in THF at 40°C, gave the cyclopentane derivative 10 in 58% yield and in 28% ee after oxidative work-up and benzoylation. Moreover, reaction of the prochiral triflate 2c with Pd2(dba)3·CHCl3, (S)-(R)-PPFA and K2CO3, in THF at 40°C, afforded the cyclopentane derivative 3b, with a quaternary carbon center, in 42% yield and in 31% ee after oxidative work-up.
- Cho, Suk Young,Shibasaki, Masakatsu
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- Decarboxylative Annulation of α-Amino Acids with β-Ketoaldehydes
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Indolizidine and quinolizidine derivatives are readily assembled from l-proline or (±)-pipecolic acid and β-ketoaldehydes via a decarboxylative annulation process. These reactions are promoted by acetic acid and involve azomethine ylides as reactive intermediates.
- Paul, Anirudra,Thimmegowda,Galani Cruz, Thiago,Seidel, Daniel
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supporting information
p. 602 - 604
(2018/02/09)
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- 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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- Phase-transfer Tsuji—Trost allylation of CH-acids with the assistance of palladium complexes with bidentate PIII—N—PIII ligands
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The Tsuji—Trost allylation of CH acids, in particular, those of the YCH2CO2Et type (Y = CO2Et, C(O)Me, CN), with allylic acetates in the K2CO3—DMF system in the presence of palladium catalysts with ligands RN(PPh2)2 (R = Ph, Pri, c-C6H11) is accomplished.
- Vasil′ev,Aladzheva,Bykhovskaya
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p. 661 - 665
(2017/09/11)
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- Highly efficient Tsuji-Trost allylation in water catalyzed by Pd-nanoparticles
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Palladium nanoparticles stabilized by poly(vinylpyrrolidone) catalyze Tsuji-Trost allylations in water with very high turnover numbers. The di-allylation of methylene active compounds and the allylation of bio-based phenols was performed in high yield. The allylation of lignin showed a high selectivity towards the phenolic OH groups.
- Llevot,Monney,Sehlinger,Behrens,Meier
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supporting information
p. 5175 - 5178
(2017/07/12)
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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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- A Pd-bisphosphine complex and organic functionalities immobilized on the same SiO2 surface: Detailed characterization and its use as an efficient catalyst for allylation
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A Pd-bisphosphine complex and several organic functionalities were immobilized on the same SiO2 surface. The samples thus prepared were characterized by solid-state NMR, XPS, and XAFS. Based on the curve-fitting analysis of Pd K-edge EXAFS spectra, both the local environment of the immobilized Pd complexes and the interactions with the co-immobilized organic functions were discussed. The SiO2-supported Pd-bisphosphine complex and DABCO exhibited excellent catalytic performance for the allylation of various nucleophiles: a TON of up to 106000 was obtained. Both the catalyst activation pathway and the reaction mechanism were also discussed on the basis of the structure of the used catalyst samples.
- Motokura, Ken,Saitoh, Koki,Noda, Hiroto,Chun, Wang-Jae,Miyaji, Akimitsu,Yamaguchi, Sho,Baba, Toshihide
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p. 5380 - 5388
(2016/07/21)
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- Enantioselective biocatalytic reduction of 2,2-disubstituted ethylacetoacetates: An indirect desymmetrization approach for the synthesis of enantiopure (S)-4-hydroxy-3,3-disubstituted pentane-2-ones
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Ethyl 2,2-disubstituted-3-oxobutanoates were biocatalytically reduced to the corresponding (S)-ethyl 3-hydroxy-2,2-disubstitutedbutanoate with the growing cells of Klebsiella pneumoniae (NBRC 3319) with excellent enantioselection. The biocatalytically derived enantiopure hydroxyl esters were then synthetically manipulated to give (S)-4-hydroxy-3,3-disubstituted pentane-2-ones. The whole process can be regarded as an indirect enantioselective enzymatic desymmetrization method for the synthesis of (S)-4-hydroxy-3,3-disubstituted pentane-2-ones.
- Halder, Joydev,Das, Debabrata,Nanda, Samik
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p. 1197 - 1208
(2015/10/28)
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- A general synthetic approach to para-cyclophanes via ring-closing metathesis
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A new methodology for the synthesis para-cyclophanes and longithorone C frameworks has been demonstrated via alkylation, ceric ammonium nitrate (CAN) oxidation and ring-closing metathesis as key steps.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
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p. 1483 - 1494
(2016/02/26)
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- A general synthetic approach to para-cyclophanes via ring-closing metathesis
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A new methodology for the synthesis para-cyclophanes, and longithorone C frameworks has been demonstrated via alkylation, eerie ammonium nitrate (CAN) oxidation and ring-closing metathesis as key steps.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
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p. 1483 - 1494
(2016/09/09)
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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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- Dual platinum and pyrrolidine catalysis in the direct alkylation of allylic alcohols: Selective synthesis of monoallylation products
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A dual platinum- and pyrrolidine-catalyzed direct allylic alkylation of allylic alcohols with various active methylene compounds to produce products with high monoallylation selectivity was developed. The use of pyrrolidine and acetic acid was essential, not only for preventing undesirable side reactions, but also for obtaining high monoallylation selectivity. Two cats are better than one: The combined use of platinum and pyrrolidine catalysts enabled the direct alkylation of allylic alcohols with reactive methylene compounds. Pyrrolidine was essential for obtaining high selectivity of the monoallylation products, which were produced without the use of excess nucleophiles. cod=1,5- cyclooctadiene, EWG=electron-withdrawing group.
- Shibuya, Ryozo,Lin, Lu,Nakahara, Yasuhito,Mashima, Kazushi,Ohshima, Takashi
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supporting information
p. 4377 - 4381
(2014/05/06)
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- First iodine-catalyzed deallylation of reactive allyl methylene esters
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C-Allyl cleavage has been developed using the inexpensive and mild reagent iodine in dimethylsulfoxide. A variety of compounds with active methylene groups were C-deallylated using this reagent. This method is efficient and operationally simple in comparison to the methods using transition-metal complexes. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Nawghare, Beena R.,Lokhande, Pradeep D.
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p. 1955 - 1963
(2013/06/05)
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- Tsuji-Trost allylation of CH acids in supercritical carbon dioxide: Advantages and problems
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The Pd(PPh3)4-catalyzed reaction between α-cyano or β-oxo carboxylates and allyl acetate in supercritical carbon dioxide with the K2CO3-18-crown-6 system as a base affords exhaustive allylation products in high yields, whereas malononitrile and acetylacetone of higher CH acidity form the mixtures of mono- and diallylated derivatives in moderate yields.
- Vasil'ev, Andrei A.,Kuchurov, Ilya V.,Zlotin, Sergei G.
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- Bifunctional mesoporous silica nanoparticles as cooperative catalysts for the Tsuji-Trost reaction-tuning the reactivity of silica nanoparticles
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Bifunctional mesoporous silica nanoparticles (MSNs) bearing Pd-complexes and additional basic sites were prepared and tested as cooperative active catalysts in the Tsuji-Trost allylation of ethyl acetoacetate. Functionalization of the MSNs was realized by postmodification using click-chemistry. The selectivity of mono versus double allylation was achieved by control of reaction temperature and the nature of the catalyst.
- Dickschat, Arne T.,Behrends, Frederik,Surmiak, Sabrina,Wei?, Mark,Eckert, Hellmut,Studer, Armido
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supporting information
p. 2195 - 2197
(2013/03/29)
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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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- Diversity-oriented approach to macrocyclic cyclophane derivatives via ring-closing metathesis
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A short synthetic approach to the macrocyclic framework of longithorone C is described via ring-closing metathesis using the Grubbs 2nd generation catalyst. Georg Thieme Verlag Stuttgart ? New York.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
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p. 2183 - 2188
(2012/11/07)
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- An unexpected directing effect in the asymmetric transfer hydrogenation of α,α-disubstituted ketones
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α,α-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound η6-arene ring in the reduction transition state.
- Soni, Rina,Collinson, John-Michael,Clarkson, Guy C.,Wills, Martin
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supporting information; experimental part
p. 4304 - 4307
(2011/10/11)
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- Scope and mechanism of intramolecular aziridination of cyclopent-3-enyl- methylamines to 1-azatricyclo[2.2.1.02,6]heptanes with lead tetraacetate
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A series of seven cyclopent-3-en-1-ylmethylamines bearing one, two, or three methyl substituents at the C2, C3, C4, or Cα positions, including the unsubstituted parent, was accessed by ring-closing metatheses of α,α-diallylacetonitrile (or methallyl variants) and α,α-diallylacetone followed by hydride reductions or reductive amination, or by Curtius degradations of α,α-dimethyl- and 2,2,3-trimethylcyclopent-3-enylacetic acids. Oxidation of the primary amines with Pb(OAc)4 in CH2Cl2, CHCl3 or benzene in the presence of K2CO3 effected efficient intramolecular aziridinations, in all cases except the α-methyl analogue (16), to form the corresponding 1-azatricyclo[2.2.1.02,6]heptanes, including the novel monoterpene analogues, 1-azatricyclene and the 2-azatricyclene enantiomers. The cumulative rate increases of aziridination reactions observed by 1H NMR spectroscopy in CDCl3 resulting from the presence of one or two methyl groups on the cyclopentene double bond, in comparison to the rate of the unsubstituted parent amine (1:17.5:>280), indicate a highly electrophilic intermediate as the nitrene donor and a symmetrical aziridine-like transition state. A mechanism is outlined in which the amine displaces an acetate ligand from Pb(OAc)4 to form a lead(IV) amide intermediate RNHPb(OAc)3 proposed as the actual aziridinating species.
- Hu, Huayou,Faraldos, Juan A.,Coates, Robert M.
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supporting information; experimental part
p. 11998 - 12006
(2009/12/08)
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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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- Nickel-catalyzed cyclization of α,ω-dienes: Formation vs. cleavage of C-C bonds
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A combination of a catalytic amount of a Ni-phosphine complex and triethylaluminium or chlorodiethylaluminium is able to selectively cyclize a number of 1,7-heptadienes to methylidene(methyl)cyclopentanes and cyclopentenes even in cases where the dienes are prone to deallylation. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.
- Necas, David,Tursky, Matyas,Tislerova, Iva,Kotora, Martin
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p. 671 - 674
(2007/10/03)
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- Imidazolium salts as phase transfer catalysts for the dialkylation and cycloalkylation of active methylene compounds
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The efficient synthesis of 1,1-disubstituted derivatives and the construction of cyclopropane and cyclopentane ring systems via dialkylation and cycloalkylation reactions of active methylene compounds using imidazolium salts as phase transfer catalyst is described. The dialkylation and cycloalkylation reactions of active methylene compounds in the presence of readily available imidazolium salts (ionic liquids) as phase transfer catalysts were performed to afford the respective dialkylated or cycloalkylated products. This method is very efficient for the synthesis of 1,1-disubstituted derivatives and cyclopropane and cyclopentane ring systems in a facile manner.
- Muthusamy, Sengodagounder,Gnanaprakasam, Boopathy
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p. 635 - 638
(2007/10/03)
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- Cascade radical cyclisations of methylenecyclopropyl ketones - Synthesis of bicyclo-[3.2.1]-octanes
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Samarium diiodide mediated cyclisation of methylenecyclopropyl ketones, readily prepared from β-ketoesters provides a simple route to bicyclo-[3.2.1]-octanes.
- Saint-Dizier, Alexandre C.,Kilburn, Jeremy D.
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p. 6201 - 6203
(2007/10/03)
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- (π-Allyl)palladium complexes bearing diphosphinidenecyclobutene ligands (DPCB): Highly active catalysts for direct conversion of allylic alcohols
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The (π-allyl)palladium complex bearing an sp2-hybridized phosphorus ligand (DPCB-OMe: 1,2-bis(4-methoxyphenyl)-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene) efficiently catalyzes direct conversion of allylic alcohols in the absence of activating agents of alcohols such as Lewis acids. N-Allylation of aniline proceeds at room temperature to afford monoallylated anilines in 90-97% yields. C-Allylation of active methylene compounds is also successful at 50 °C using a catalytic amount of pyridine as a base, giving monoallylation products in 85-95% yields. The catalytic mechanism involving hydrido- and (π-allyl)palladium intermediates has been proposed on the basis of stoichiometric examinations using model compounds of presumed intermediates. Copyright
- Ozawa, Fumiyuki,Okamoto, Hideyuki,Kawagishi, Seiji,Yamamoto, Shogo,Minami, Tatsuya,Yoshifuji, Masaaki
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p. 10968 - 10969
(2007/10/03)
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- Palladium-tetraphosphine complex: An efficient catalyst for allylic substitution and Suzuki cross-coupling
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A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis (diphenylphosphinomethyl)cyclopentane (Tedicyp) has been synthesized and used in palladium-catalyzed reactions. This tetraphosphine in combination with [Pd(C3H5)Cl]2 affords a very efficient catalyst for coupling reactions. Turnover numbers of 980 000 for allylic amination, 9 800 000 for allylic alkylation and 97 000 000 for Suzuki cross-coupling can be obtained in the presence of this catalyst.
- Feuerstein,Laurenti,Doucet,Santelli
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p. 2320 - 2326
(2007/10/03)
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- A new tetratertiary phosphine ligand and its use in Pd-catalyzed allylic substitution
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A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) 1 has been synthesized, characterized, and used in Pd-catalyzed allylic substitutions. The Tedicyp was easily prepared in seven steps from the commercially available himic anhydride. The structure of the complex Tedicyp-borane was determined by X-ray analysis. The tetraphosphine in combination with [Pd(η3-C3H5)Cl]2 affords a very efficient catalyst for allylic substitution of several allylic acetates. Under mild conditions, very high turnover numbers and turnover frequencies have been obtained.
- Laurenti,Feuerstein,Pepe,Doucet,Santelli
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p. 1633 - 1637
(2007/10/03)
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- Use of the Nonionic Superbase P(MeNCH2CH2)3N in the Selective Monoalkylation of Active-Methylene Compounds
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The symmetric active-methylene compounds CH2(CO2Et)2 and CH2[C(O)Me]2 are selectively monoalkylated in the presence of 1.1 equiv of a variety of alkyl halides and 1 equiv of the nonionic Superbase P(MeNCH2CH2)2N in 85-98% yields in 30 min at room temperature. The unsymmetrical active-methylene compound EtO2CCH2C(O)Me is selectively monoalkylated under the same conditions, except for the temperature, which is 0 °C, in 59-88% yields. The observation of selective C- rather than O-alkylation is rationalized in terms of the formation of an enolate whose negatively charged oxygen is sterically protected by a nearby HP(MeNCH2CH2)2N+ counterion in a tight ion pair.
- Arumugam, Subramaniam,McLeod, Dale,Verkade, John G.
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p. 3677 - 3679
(2007/10/03)
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- Reaction of tetracarbonyl(π-allyl)manganese with carbon nucleophiles
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Nucleophilic attack on tetracarbony (π-allyl)manganese takes place at the terminus of the π-system, generating allylated products in 44-95% yield after oxidation. Stabilized nucleophiles (pK(a) 12-20) give mainly bis allylation whereas nonstabilized nucleophiles (pKa 25-35) give mono allylation.
- Vaughan, William S.,Gu, Henry H.,McDaniel, Keith F.
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p. 1885 - 1888
(2007/10/03)
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- Palladium Catalysed Direct Allylation of Pronucleophiles with Allylstannanes
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The reaction of pronucleophiles 1 with allyltributylstannanes in the presence of catalytic amounts of Pd2(dba)3*CHCl3 (4 molpercent) and 1,2-bis(diphenylphosphino)ethane (dppe) (10 molpercent) at room temperature gives the corresponding allylation products in good to high yields.
- Yamamoto, Yoshinori,Fujiwara, Naoya
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p. 2013 - 2014
(2007/10/02)
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- Ruthenium complex-catalyzed allylic alkylation of carbonucleophiles with allylic carbonates
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Allylic carbonates except for allyl methyl carbonate reacted with carbonucleophiles such as ethyl acetoacetate in the presence of a catalytic amount of Ru(cod)(cot) in N-methylpiperidine at 80 deg C to give the corresponding monoallylated carbonucleophiles in high yields with high regioselectivity.The regioselectivity was quite different from that in the palladium-catalyzed reactions.The allylation of carbonucleophiles using allyl methyl carbonate selectively gave the diallylated carbonucleophiles in high yields.
- Zhang, Shi-Wei,Mitsudo, Take-aki,Kondo, Teruyuki,Watanabe, Yoshihisa
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p. 197 - 207
(2007/10/02)
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- SELECTIVE C-ALKYLATION OF 1,3-DICARBONYL COMPOUNDS
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Lithium hydroxide-mediated alkylation of 1,3-dicarbonyl compounds proves to proceed with high efficiency and selectivity.
- Antonioletti, Roberto,Bonadies, Francesco,Orelli, Liliana Raquel,Scettri, Arrigo
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p. 237 - 238
(2007/10/02)
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- Surface-mediated Solid-phase Reaction. Part 2. Highly Selective Mono- and Di-C-alkylation of 1,3-Dicarbonyl Compounds on the Surface of Alumina
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Highly selective mono- and di-C-alkylation of 1,3-dicarbonyl compounds with different, structurally varied alkyl halides has been achieved in high yields through a simple solvent-free reaction on the surface of alumina impregnated with sodium or potassium alkoxide.
- Ranu, Brindaban C.,Bhar, Sanjay
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p. 365 - 368
(2007/10/02)
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- Highly Stereoselective Palladium(0)-Catalyzed Allylation of Active Methylene Compounds with Allyl Imidates under Neutral Conditions
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In the presence of a catalytic amount of Pd(0), active methylene compounds were allylated by allyl imidates under neutral conditions.In allylation with 3,3-disubstituted allyl imidates, e.g., geranyl and neryl imidate the effect of solvent and ligand to the E/Z ratio are investigated.The reaction in dimethyl sulfoxide by addition of diphosphine, e.g., 1,2-bis(diphenylphosphino)ethane, or large excess of triphenylphosphine as additive ligand gave best results.In these conditions, various active methylene compounds were allylated stereoselectively, especially complete retention of starting olefin geometry was achieved with neryl imidate.
- Suzuki, Osamu,Inoue, Seiichi,Sato, Kikumasa
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p. 239 - 243
(2007/10/02)
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- Polyethylene-Bound Soluble Recoverable Palladium(0) Catalysts
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The use of diphenylphosphine-terminated ethylene oligomers as ligands for palladium(0) and palladium(II) is described.With use of these polymeric ligands, it is possible to carry out homogeneous reactions characteristic of (Ph3P)4Pd and (Ph3P)2Pd(OAc)2 with essentially complete recovery of the Pd catalyst.The only limitation to repeated reuse of the catalyst is its immolative catalytic oxidation of the phosphine ligand by adventitious oxygen.
- Bergbreiter, David E.,Weatherford, David A.
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p. 2726 - 2730
(2007/10/02)
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- Palladium-catalyzed allylic alkylation of carbonucleophiles with allylic borates or allylic alcohols and boron oxide under neutral conditions
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Under neutral conditions, Pd(PPh3)4 catalyzes the allylic alkylation of carbonucleophiles with allylic borates in high yields.Moreover, allylic borates are formed in situ from allylic alcohols with boron oxide, and the Pd-catalyzed allylic alkylation was achieved simply by the reaction of allylic alcohols with a nucleophile in the presesnce of boron oxide by a one-pot procedure.The mechanisms of these reactions are discussed.
- Lu, Xiyan,Jiang, Xiaohui,Tao, Xiaochun
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p. 109 - 118
(2007/10/02)
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- Allylation of Active Methylene Compounds with Allyl Oxime Carbonates Catalyzed by Pd(0)
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Allylation of active methylene compounds catalyzed by a palladium(0)-phosphine system took place highly stereoselectively by employing allyl oxime carbonates as the allylating reagent.
- Suzuki, Osamu,Hashiguchi, Yoshiharu,Inoue, Seiichi,Sato, Kikumasa
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p. 291 - 294
(2007/10/02)
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- Process for the production of allyl acetone
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A process is described for the preparation of allyl acetone (5-hexen-2-one) according to the reaction: STR1 wherein R is methyl or ethyl; X is chloro or bromo; M is sodium or potassium; and Q is sodium or potassium, the reaction being carried out (i) using a phase transfer agent and (ii) in a two phase system.
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