- Development of a One-Pot Four C-C Bond-Forming Sequence Based on Palladium/Ruthenium Tandem Catalysis
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A one-pot four C-C bond-forming sequence has been developed using two distinct transition metal complexes. The sequence entails a double Pd-catalyzed allylic alkylation followed by a Ru-catalyzed ring-closing metathesis and a Pd-catalyzed Heck coupling. The use of various active methylene nucleophiles was examined with yields up to 76% (93% per C-C bond).
- Manick, Anne-Doriane,Berhal, Farouk,Prestat, Guillaume
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supporting information
p. 194 - 197
(2018/01/17)
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- Catalytic C?C Bond Formation Using a Simple Nickel Precatalyst System: Base- and Activator-Free Direct C-Allylation by Alcohols and Amines
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A “totally catalytic” nickel(0)-mediated method for base-free direct alkylation of allyl alcohols and allyl amines is reported. The reaction is selective for monoallylation, uses an inexpensive NiII precatalyst system, and requires no activating reagents to be present.
- Sweeney, Joseph B.,Ball, Anthony K.,Smith, Luke J.
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supporting information
p. 7354 - 7357
(2018/05/03)
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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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- Diastereoselective carbocyclization of 1,6-heptadienes triggered by rhodium-catalyzed activation of an olefinic C-H bond
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The use of α,ω-dienes as functionalization reagents for olefinic carbon-hydrogen bonds has been rarely studied. Reported herein is the rhodium(I)-catalyzed rearrangement of prochiral 1,6-heptadienes into [2,2,1]-cycloheptane derivatives with concomitant creation of at least three stereogenic centers and complete diastereocontrol. Deuterium-labeling studies and the isolation of a key intermediate are consistent with a group-directed C-H bond activation, followed by two consecutive migratory insertions, with only the latter step being diastereoselective. Folding alkenes: Described is the first example of a rhodium(I)-catalyzed functionalization of an olefinic C-H bond with a 1,6-heptadiene reagent. This carbocyclization is completely diastereoselective and creates at least three stereogenic centers from simple prochiral substrates. The directing group can easily be converted into other functional groups.
- Aissa, Christophe,Ho, Kelvin Y. T.,Tetlow, Daniel J.,Pin-No, Maria
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supporting information
p. 4209 - 4212
(2014/05/06)
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- Ruthenium-Catalyzed One-Pot Double Allylation/Cycloisomerization of 1,3-Dicarbonyl Compounds Leading to exo-Methylenecyclopentanes
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The ruthenium-catalyzed one-pot double allylation/cycloisomerization of 1,3-diketones and methyl acetoacetate gave exo-methylenecyclopentanes in moderate to good yields with high isomer selectivity. The double allylation step effectively proceeded in the presence of a RuII precatalyst, [Cp*RuCl(cod)], in 1,2-dichloroethane at 90°C. The subsequent cycloisomerization was carried out upon addition of triethylsilane as a hydride source without purification of a 1,6-diene intermediate. Detailed inspections of the reaction by 1H NMR spectroscopy disclosed that triethylsilyl methyl ether plays an important role for the conversion of a ruthenium(IV) allyl complex formed in the double allylation step into a ruthenium(II) species required for the cycloisomerization.
- Yamamoto, Yoshihiko,Nakagai, Yu-Ichiro,Itoh, Kenji
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p. 231 - 236
(2007/10/03)
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- Triethylborane as an efficient promoter for palladium-catalyzed allylation of active methylene compounds with allyl alcohols
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Without prior activation of allyl alcohols, allylation of a variety of active methylene compounds with allyl alcohols proceeds smoothly at rt-50°C in the presence of catalytic amounts of Pd(OAc)2 (1-10mol%), Et 3B (30-240mol%), a phosphine ligand (1-20mol%), and a base (0 to 50-60mol%).
- Kimura, Masanari,Mukai, Ryutaro,Tanigawa, Naoko,Tanaka, Shuji,Tamaru, Yoshinao
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p. 7767 - 7777
(2007/10/03)
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- Mono and diphosphine borane complexes grafted on polypyrrole matrix: Direct use as supported ligands for Rh and Pd catalysis
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A new versatile method for the synthesis of supported mono and diphosphines on polypyrrole matrix is described, based on the protective borane complexation of the phosphorus atom. For the first time, the unknown alkylation of a diphosphine ethano bridge, was obtained with near yield close to 70%, leading to its derivative 8 bearing the polymerizable pyrrole group on a side chain. The different supported mono and diphosphine boranes 12-15 have been applied with success in palladium-catalyzed allylation, cross-coupling reaction and in rhodium-catalyzed hydrogenation. It is of particular interest that supported phosphine boranes can be used without previous decomplexation, forming in situ the catalytically active species from Pd(OAc)2 or RhCl3. Moreover, the recoverable polymer could be used again in rhodium-catalyzed hydrogenation with a very good efficiency after several turn-overs. Nethertheless, we may point out that with palladium catalysis, the addition of Pd(dba)2 was necessary to recover the catalytic activity. These results demonstrate that the phosphine borane complexes are key precursors for the synthesis of functionalized mono and diphosphines, and for their direct use in generating catalysts.
- Riegel, Nadege,Darcel, Christophe,Stephan, Olivier,Juge, Sylvain
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p. 219 - 233
(2007/10/03)
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- Efficient coupling reactions of allylamines with soft nucleophiles using nickel-based catalysts
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Substitution reactions of N,N-diethylallylamine 1 with soft nucleophiles such as active methylene compounds 2a-c and piperidine 5 proceed much more rapidly in the presence of Ni(dppb)2 [dppb = 1,4-bis(diphenylphosphino)butane] as catalyst than with comparable palladium systems.
- Bricout, Herve,Carpentier, Jean-Francois,Mortreux, Andre
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p. 1393 - 1394
(2007/10/03)
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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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- Process for preparing valproic acid
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A process for preparing valproic acid which comprises: (I) producing a 2,2-dipropyl acetoacetic acid ester from an acetoacetic acid ester, (II) deacetylating the 2,2-dipropyl acetoacetic acid ester with an alcohol to give a valproic acid ester, and (III) hydrolyzing the valproic acid ester. In the process of the present invention, valproic acid can be prepared in a high yield as not less than 85% by mole and by-products such as α-propyl-β-ethyl acrylic acid and its esters which cannot be easily separated from valproic acid, are not entirely produced.
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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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