- Nickel-Catalyzed Cross-Coupling of Allyl Alcohols with Aryl- or Alkenylzinc Reagents
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Nickel-catalyzed cross-coupling of allyl alcohols with aryl- and alkenylzinc chlorides through C-O bond cleavage was performed. Reaction of (E)-3-phenylprop-2-en-1-ol and 1-aryl-prop-2-en-1-ols with aryl- or alkenylzinc chlorides gave linear cross-coupling products. Reaction of 1-phenyl- or 1-methyl-substituted (E)-3-phenylprop-2-en-1-ol with aryl- or alkenylzinc chlorides resulted in 3-aryl/alkenyl-substituted (E)-(prop-1-ene-1,3-diyl)dibenzenes or 3-aryl/alkenyl-substituted (E)-(but-1-enyl)benzene. Reaction of allyl alcohol with p-Me2NC6H4ZnCl resulted in a mixture of normal coupling product 4-allyl-N,N-dimethylaniline and its isomerized product N,N-dimethyl-4-(prop-1-en-1-yl)aniline.
- Yang, Bo,Wang, Zhong-Xia
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p. 4542 - 4549
(2017/05/12)
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- Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes
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In the presence of bidentate 1,n-bis-diphenylphosphinoalkane-CoCl2 complexes {Cl2Co[P ~ P]} and Me3Al or methylaluminoxane, acyclic (E)-1,3-dienes react with ethylene (1 atmosphere) to give excellent yields of hydrovinylat
- Timsina, Yam N.,Sharma, Rakesh K.,Rajanbabu
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p. 3994 - 4008
(2015/06/25)
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- Triarylphosphine ligands with hemilabile alkoxy groups: Ligands for nickel(II)-catalyzed olefin dimerization reactions. hydrovinylation of vinylarenes, 1,3-dienes, and cycloisomerization of 1,6-dienes
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Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl- and 2-benzyloxymethylphenyldiphenylphosphine (L5 and L6, respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at -55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, affording up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II) complexes of 2- benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl- (L6) and 2-benzyloxyethyldiphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II) complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II) complexes of N-heterocyclic carbene ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions.
- Biswas, Souvagya,Zhang, Aibin,Raya, Balaram,Rajanbabu
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p. 2281 - 2292
(2014/07/21)
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- A novel catalytic asymmetric route towards skipped dienes with a methyl-substituted central stereogenic carbon
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A highly efficient method for the enantioselective synthesis of 1,4-dienes (skipped dienes) with a methyl-substituted central stereogenic carbon using copper-catalysed asymmetric allylic alkylation of diene bromides was developed. Excellent regio- and enantioselectivity (up to 97 : 3 SN2′/ SN2 ratio and 99% ee) were achieved with broad substrate scope. The Royal Society of Chemistry 2013.
- Huang, Yange,Fananas-Mastral, Martin,Minnaard, Adriaan J.,Feringa, Ben L.
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p. 3309 - 3311
(2013/06/04)
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- Self-assembled poly(imidazole-palladium): Highly active, reusable catalyst at parts per million to parts per billion levels
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Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts. Thus, a metalloenzyme-inspired polymeric imidazole Pd catalyst (MEPI-Pd) was readily prepared by the coordinative convolution of (NH4)2PdCl4 and poly[(N-vinylimidazole)-co-(N- isopropylacrylamide)5] in a methanol-water solution at 80 °C for 30 min. SEM observation revealed that MEPI-Pd has a globular-aggregated, self-assembled structure. TEM observation and XPS and EDX analyses indicated that PdCl2 and Pd(0) nanoparticles were uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20 000-1 250 000. Furthermore, MEPI-Pd efficiently promoted the Suzuki-Miyaura reaction of a variety of inactivated aryl chlorides as well as aryl bromides and iodides in water with a TON of up to 3 570 000. MEPI-Pd was reused for the allylic arylation and Suzuki-Miyaura reaction of an aryl chloride without loss of catalytic activity.
- Yamada, Yoichi M. A.,Sarkar, Shaheen M.,Uozumi, Yasuhiro
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supporting information; experimental part
p. 3190 - 3198
(2012/04/10)
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- Nickel-catalyzed allylic substitution of simple alkenes
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This report describes a nickel-catalyzed allylic substitution process of simple alkenes whereby an important structural motif, a 1,4-diene, was prepared. The key to success is the use of an appropriate nickel-phosphine complex and a stoichiometric amount of silyl triflate. Reactions of 1-alkyl-substituted alkenes consistently provided 1,1-disubstituted alkenes with high selectivity. Insight into the reaction mechanism as well as miscellaneous application of the developed catalytic process is also documented.
- Matsubara, Ryosuke,Jamison, Timothy F.
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p. 1860 - 1875
(2012/02/02)
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- A highly active and reusable self-assembled poly(imidazole/palladium) catalyst: Allylic arylation/alkenylation
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Gobs of globules: A polymeric imidazole/acrylamide palladium catalyst, MPPI-Pd (M=PdIICl and Pd0), was utilized for the allylic arylation/alkenylation of allylic esters with aryl/alkenylboronic acids and tetraaryl borates. Low catalyst loadings efficiently promoted the reaction with a catalytic turnover number of 20000-1250000. The catalyst can be reused without loss of catalytic activity.
- Sarkar, Shaheen M.,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
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supporting information; experimental part
p. 9437 - 9441
(2011/11/06)
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- Cu(I)-catalyzed, α-selective, allylic alkylation reactions between phosphorothioate esters and organomagnesium reagents
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Regiocontrol of allylic alkylation reactions involving hard nucleophiles remains a significant challenge and continues to be an active area of research. The lack of general methods in which α-alkylation is favored underscores the need for the development of new processes for achieving this type of selectivity. We report that Cu(I) catalyzes the allylic substitution of phosphorothioate esters with excellent α-regioselectivity, regardless of the nature of the Grignard reagent that is used. To the best of our knowledge, the Cu-catalyzed allylic alkylation of phosphorothioate esters has never been described. We have also developed a simple protocol for inducing high α selectivity starting from secondary allylic halides. This is accomplished by using sodium phosphorothioates as an additive.
- Lauer, Andrew M.,Mahmud, Farzeen,Wu, Jimmy
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p. 9119 - 9123
(2011/08/04)
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- Nickel-catalyzed allylic substitution of simple alkenes
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Nickel-catalyzed intermolecular allylic substitution of simple alkenes (ethylene and alpha olefins) is described. This method is the first catalytic intermolecular process for direct allylation of nonconjugated, nonstrained simple alkenes. Catalyst loadings as low as 2.5 mol % Ni afford the desired product in high yield in both gram-scale and smaller scale coupling reactions.
- Matsubara, Ryosuke,Jamison, Timothy F.
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supporting information; experimental part
p. 6880 - 6881
(2010/07/05)
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- Nickel-catalyzed cross-coupling reaction of allyl- and benzylzinc with alkenyl sulfides
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Alkenyl Sulfides can be utilized for nickel-catalyzed cross-coupling reactions with allyl- and benzylzinc reagents.
- Baba, Yoko,Toshimitsu, Akio,Matsubara, Seijiro
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scheme or table
p. 2061 - 2063
(2009/04/11)
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- Cross-coupling reaction of allylic and benzylic carbonates with organo[2-(hydroxymethyl)phenyl]dimethylsilanes
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The title reaction is found to proceed in the presence of a palladium catalyst and in the absence of any activator. Various functional groups are tolerated to give a diverse range of 1,4-diene and diarylmethane products, which are ubiquitous units of natural products and pharmaceuticals. Copyright
- Nakao, Yoshiaki,Ebata, Shiro,Chen, Jinshui,Imanaka, Hidekazu,Hiyama, Tamejiro
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p. 606 - 607
(2008/02/07)
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- Hydrovinylation of 1,3-dienes: A new protocol, an asymmetric variation, and a potential solution to the exocyclic side chain stereochemistry problem
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Cyclic and acyclic 1,3-dienes undergo efficient (substrate/catalyst = 72) heterodimerization with ethylene in the presence of a Ni catalyst prepared from [o-(PhCH2O)]C6H4PPh2, [(allyl)2NiBr]2, and Na+ BAr4- (Ar = 3,5-bis-trifluromethylphenyl), giving 1,2-addition products. Yields up to 99% can be realized for several 1-vinylcycloalkenes and 1-substituted 1,3-butadienes. Phospholanes with suitably placed hemilabile ligating groups and phosphoramidites derived from binaphthol are excellent ligands for an asymmetric variation of this reaction, the latter giving 99% yield and >95% ee's for selected substrates. An example of how an exocyclic chiral center can be used to install other stereo-centers in the ring (e. g., the carbon to which the side chain is attached) is also provided. These discoveries open an expeditious entry into several biologically relevant classes of compounds, especially those carrying tetrahydronaphthalene and related heterocyclic moieties. Copyright
- Zhang, Aibin,RajanBabu
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- The Palladium-Catalyzed Cross-Coupling Reaction of Organosilicon Compounds with Allylic Carbonates or Diene Monoxides
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The cross-coupling reaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst.The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon reagent.Likewise, diene monoxides also underwent cross-coupling with alkenyl- and arylfluorosilanes in moderate to high yields.
- Matsuhashi, Hayao,Asai, Satoshi,Hirabayashi, Kazunori,Hatanaka, Yasuo,Mori, Atsunori,Hiyama, Tamejiro
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p. 1943 - 1952
(2007/10/03)
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- Palladium-catalyzed cross-coupling of allylic carbonates with alkenylfluorosilanes in the absence of fluoride ion
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Alkenylfluorosilanes smoothly underwent cross-coupling reaction with allylic carbonates in the presence of a palladium catalyst and in the absence of fluoride ion to give 1,4-dienes in good yields with retention of configuration.
- Matsuhashi, Hayao,Hatanaka, Yasuo,Kuroboshi, Manabu,Hiyama, Tamejiro
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p. 1539 - 1540
(2007/10/02)
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- Syntheses of 1,3- and 1,4-Dienes by the Oxidative Coupling of 1-Alkenylstannanes and 2-Alkenylstannanes in the Presence of Palladium Catalyst
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Treatment of 1-alkenylstannanes with tBuOOH in the presence of palladium catalyst gives 1,3-dienes.Cross coupling reaction between 1-alkenylstannanes and 2-alkenylstannanes provides 1,4-dienes selectively in good yields.
- Kanemoto, Shigekazu,Matsubara, Seijiro,Oshima, Koichiro,Utimoto, Kiitiro,Nozaki, Hitosi
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