- Asymmetric Synthesis Catalyzed by Chiral Ferrocenylphosphine-Transition-Metal Complexes. 6. Practical Asymmetric Synthesis of 1,1'-Binaphthyls via Asymmetric Cross-Coupling with a Chiral monophosphine/Nickel Catalyst.
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Cross-coupling of (2-methyl-1-naphthyl)magnesium bromide (1a) with 2-methyl-1-naphthyl bromide (2a) at -15 or 0 deg C in the presence of nickel catalyst prepared in situ from nickel bromide and (S)-1-ethyl methyl ether (3a) gave high yield of (R)-(-)-2,2'-dimethyl-1,1'-binaphthyl (4a) in up to 95percent ee.Ferrocenylphosphine 3a was also effective for the reaction of 1a with 1-naphthyl bromide (2b) and that of (2-ethyl-1-naphthyl)magnesium bromide (1c) with 2b to give corresponding cross-coupling products in 83 and 77percent ee, respectively.
- Hayashi, Tamio,Hayashizaki, Keiichi,Kiyoi, Takao,Ito, Yoshihiko
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- Synthesis of axially chiral 1,1′-binaphthalenes by palladium-catalysed cross-coupling reactions of triorganoindium reagents
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1,1′-Binaphthalenes and heterocyclic analogues can be efficiently prepared by palladium-catalysed cross-coupling reactions between tri(1-naphthyl)indium reagents and 1-halonaphthalenes and haloisoquinolines. The reactions were usually carried out in THF at 80 °C with a slight excess of the indium reagent (40 mol-%) and a low catalyst loading (4 mol-% Pd) to afford the cross-coupling products in good yields (45-99 %). The method allows the synthesis of sterically hindered 2-substituted and 2,2′-disubstituted 1,1′-binaphthalenes and naphthylisoquinolines. In addition, the coupling reactions can be performed enantioselectively and the best enantiomeric excesses were obtained by using the chiral amino-phosphane ferrocenyl ligand (R,S)-PPFA. 1,1′-Binaphthalenes and heterocyclic derivatives have been synthesized by palladium-catalysed cross-coupling reactions between tri(1-naphthyl)indium reagents and 1-halonaphthalenes and haloisoquinolines, including 2-substituted and 2,2′-disubstituted 1,1′-binaphthyls. The coupling reactions can be performed enantioselectively in the presence of the chiral ligand (R,S)-PPFA. Copyright
- Mosquera, Angeles,Pena, Miguel A.,Sestelo, Jose Perez,Sarandeses, Luis A.
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- The X-ray Structures of (R)-2,2′-Dimethyl-1,1′-binaphthyl and (±)-2-Bromomethyl-2′-dibromomethyl-1,1′-binaphthyl
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Molecular structures of (R)-2,2′-dimethyl-1,1′-binaphthyl [monoclinic, a = 11.24420 (11), b = 10.56190 (9), c = 13.27180 (13) ?, β = 90.7041 (9)°, space group P21] and (±)-2-bromomethyl-2′-dibromomethyl-1,1′-binaphthyl [triclinic, a = 9.4637 (14), b = 9.9721 (18), c = 9.9922 (19) ?, α = 100.093 (5), β = 97.141 (5), γ = 92.585 (4)°, space group P-1] are reported and compared with those of other simple 2,2′-disubstituted-1,1′-binaphthyls. Graphic Abstract: Inter-ring bond length and torsion angles are compared with other simple 2,2′-disubstututed-1,1′-binaphthyls.[Figure not available: see fulltext.]
- Aitken, R. Alan,Inwood, Ryan A.,Slawin, Alexandra M. Z.
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- An enantioselective artificial Suzukiase based on the biotin-streptavidin technology
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Introduction of a biotinylated monophosphine palladium complex within streptavidin affords an enantioselective artificial Suzukiase. Site-directed mutagenesis allowed the optimization of the activity and the enantioselectivity of this artificial metalloenzyme. A variety of atropisomeric biaryls were produced in good yields and up to 90% ee. The hybrid catalyst described herein shows comparable TOF to the previous aqueous-asymmetric Suzuki catalysts, and excellent stability under the reaction conditions to realize higher TON through longer reaction time.
- Chatterjee, Anamitra,Mallin, Hendrik,Klehr, Juliane,Vallapurackal, Jaicy,Finke, Aaron D.,Vera, Laura,Marsh, May,Ward, Thomas R.
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- Synthesis and catalytic activity of chiral dicarbene dipalladium complexes incorporating the S-binaphthol unit
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A series of chiral di-N-heterocyclic carbene (NHC) dipalladium complexes, [{PdPyCl2}2(di-NHC)], in which di-NHC represents a diimidazolylidene, featuring an (S)-3,3'-dimethyl-2,2'-dimethoxy-1,1'-binaphthalene spacer between the carbene units, have been prepared. The influence of ligand size on the catalytic activity of these complexes in the Suzuki reaction of phenylboronic acid with p-bromotoluene has been investigated. The most sterically hindered complex, bearing the di-isopropylphenyl group, showed the greatest catalytic activity, and it is active for various aryl halides with different electronic and steric properties.
- Zhang, Guowen,Chao, Man,Wang, Shuting,Zhu, Mengxia,Wang, Dou,Pang, Guangsheng,Shi, Yanhui
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- Reductive opening of 2,7-dihydrodinaphthoxepine and thiepine: Easy regioselective preparation of 2,2′-difunctionalised binaphthyls
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The lithiation of 2,7-dihydrodinaphthoheteroepines (5) with 2.2 equiv of lithium naphthalenide in THF at -78°C gives dianionic intermediates 8, which by reaction with different electrophiles [H2O, D2O, tBuCHO, Me2CO, Et2CO, (CH2) 4CO, (CH2)5CO] at the same temperature, followed by hydrolysis, leads to unsymmetrically 2,2′-disubstituted binaphthyls 6. When the lithiation is performed with an excess of lithium in the presence of a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 10 mol %), a double reductive cleavage takes place to give dianionic intermediate 9, which by reaction with different electrophiles [H2O, Me 2CO, Et2CO, (CH2)4CO, (CH 2)5CO], followed by hydrolysis with water, yields symmetrically 2,2′-disubstituted binaphthyls 7. In the case of starting from (R)-5a, the reductive opening by treatment with 2.2 equiv of lithium naphthalenide followed by reaction with H2O or (CH2) 5CO as electrophiles and final hydrolysis, leads to enantiomerically pure compounds (R)-6aa and (R)-6af, respectively.
- Foubelo, Francisco,Moreno, Benjamín,Yus, Miguel
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- Asymmetric Negishi reaction for sterically hindered couplings: synthesis of chiral binaphthalenes
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A new synthetic approach affording, for the first time chiral binaphthalene derivatives via an asymmetric Negishi reaction, in good yields (55-95%) and good enantioselectivities (49-85% ee), is reported.
- Genov, Miroslav,Fuentes, Beatriz,Espinet, Pablo,Pelaz, Beatriz
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Read Online
- Application of a Ferrocene-Based Palladacycle Precatalyst to Enantioselective Aryl-Aryl Kumada Coupling
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The palladium catalysed reaction of 1-iodo-2-methylnaphthalene and 2-methyl-1-naphthylmagnesium bromide gave quantitatively an (Sa)-configured cross-coupled product in 80 % e.e. using (R,Sp)-PPFA as a ligand. N,N-Dimethylaminomethylferrocene was cyclopalladated (Na2PdCl4, (S)?Ac?Phe?OH, 93 % e.e., as determined by 1H NMR as a result of self-induced non-equivalence), and the resulting (Sp)-configured dimeric palladacycle was employed as a precatalyst for this cross-coupling reaction (5 mol%). Addition to the palladacycle of diphenylphosphine and subsequent base-promoted bidentate ligand synthesis and palladium capture gave an in situ generated catalyst resulting in an (Sp)-configured product in up to 71 % e.e.
- Arthurs, Ross A.,Hughes, David L.,Richards, Christopher J.
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supporting information
(2022/02/21)
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- Enantioselective cross-coupling for axially chiral tetra-ortho-substituted biaryls and asymmetric synthesis of gossypol
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The axially chiral tetra-ortho-substituted biaryl skeleton exists in numerous biologically important natural products, pharmaceutical molecules, chiral catalysts, and ligands. The efficient synthesis of chiral tetra-ortho-substituted biaryl structures rem
- Yang, He,Sun, Jiawei,Gu, Wei,Tang, Wenjun
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supporting information
p. 8036 - 8043
(2020/05/27)
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- Design of Phosphinic Acid Catalysts with the Closest Stereogenicity at the α-Position: Synthesis and Application of α-Stereogenic Perfluoroalkyl Phosphinic Acid Catalysts
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Chiral C2-symmetric phosphinic acids were designed based on sterically demanding and helical chiral perfluoroalkyl groups at the closest α-position advancing asymmetric reaction environment and catalytic activity. The perfluoroalkyl catalysts,
- Fujii, Kohei,Todani, Haruki,Ito, Shigekazu,Mikami, Koichi
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supporting information
(2019/05/08)
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- Single-component, low molecular weight organic supergelators based on chiral barbiturate scaffolds
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We report here the first chiral barbiturate to act as a single-component LMOG capable of gelating a variety of chlorinated and aromatic solvents. Solution-based DOSY NMR experiments, solid-state VP-SEM, and X-ray crystallography techniques were used to ch
- Seidenkranz, Daniel T.,Langworthy, Kurt A.,Zakharov, Lev N.,Pluth, Michael D.
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p. 499 - 507
(2019/06/27)
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- Large Scale Synthesis of Chiral (3 Z,5 Z)-2,7-Dihydro-1H-azepine-Derived Hamari Ligand for General Asymmetric Synthesis of Tailor-Made Amino Acids
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An advanced process for large scale (500 g) preparation of a (3Z,5Z)-2,7-dihydro-1H-azepine-derived chiral tridentate ligand (Hamari ligand), widely used for asymmetric synthesis of tailor-made α-amino acids via the corresponding glycine Schiff base Ni(II
- Takahashi, Motohiro,Moriwaki, Hiroki,Miwa, Toshio,Hoang, Brittanie,Wang, Peng,Soloshonok, Vadim A.
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p. 619 - 628
(2019/04/30)
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- NOVEL CHIRAL DIHYDROBENZOAZAPHOSPHOLE LIGANDS AND SYNTHESIS THEREOF
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This invention relates to novel phosphorous ligands useful for organic transformations. Methods of making and using the ligands in organic synthesis are described. The invention also relates to processes for preparing the novel ligands.
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Paragraph 0145; 0146
(2018/06/15)
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- Computationally Assisted Mechanistic Investigation and Development of Pd-Catalyzed Asymmetric Suzuki-Miyaura and Negishi Cross-Coupling Reactions for Tetra- ortho-Substituted Biaryl Synthesis
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Metal-catalyzed cross-coupling reactions are extensively employed in both academia and industry for the synthesis of biaryl derivatives for applications to both medicine and material science. Application of these methods to prepare tetra-ortho-substituted
- Patel, Nitinchandra D.,Sieber, Joshua D.,Tcyrulnikov, Sergei,Simmons, Bryan J.,Rivalti, Daniel,Duvvuri, Krishnaja,Zhang, Yongda,Gao, Donghong A.,Fandrick, Keith R.,Haddad, Nizar,Lao, Kendricks So,Mangunuru, Hari P. R.,Biswas, Soumik,Qu, Bo,Grinberg, Nelu,Pennino, Scott,Lee, Heewon,Song, Jinhua J.,Gupton, B. Frank,Garg, Neil K.,Kozlowski, Marisa C.,Senanayake, Chris H.
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p. 10190 - 10209
(2018/10/20)
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- Supramolecular Polymerization of [5]Helicenes. Consequences of Self-Assembly on Configurational Stability
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The supramolecular polymerization of [5]helicenes 1 and 2 is investigated. The self-assembly of these helicenes proceeds by the operation of H-bonding interactions with a negligible participation of π-stacking. The enantiopurity of the sample has a dramatic effect on the supramolecular polymerization mechanism since it reverts the isodesmic mechanism for the racemic mixture to a cooperative one for the enantioenriched sample. Noticeably, the formation of supramolecular polymers efficiently increases the configurational stability of 1,14-unsubstituted [5]helicenes.
- Valera, Jorge S.,Gómez, Rafael,Sánchez, Luis
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p. 2020 - 2023
(2018/04/16)
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- A Binaphthyl-Based Scaffold for a Chiral Dirhodium(II) Biscarboxylate Ligand with α-Quaternary Carbon Centers
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A chiral dirhodium(II) paddlewheel complex has been synthesized from biscarboxylate ligands derived from BINOL, and the resulting complex has been used in enantioselective carbene/alkyne cascade reactions. The ligand design was guided by requirements of α
- Chen, Po-An,Setthakarn, Krit,May, Jeremy A.
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p. 6155 - 6161
(2017/09/15)
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- Palladium-Catalyzed Asymmetric Suzuki-Miyaura Cross Coupling with Homochiral Phosphine Ligands Having Tetrahydro-1 H -imidazo[1,5-a ]indole Backbone
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Amphiphilic polystyrene-poly(ethylene glycol) resin-supported chiral imidazoindole phosphines (PS-PEG-L?), (3R,9aS)-2-aryl-3-(2-dialkylphosphino)phenyltetrahydro-1H-imidazo[1,5-a]indol-1-one, bearing PPh2, P(t-Bu)2, and P(c-Hex)2 groups were designed and prepared with a view toward using them in aqueous heterogeneous asymmetric Suzuki-Miyaura biaryl coupling. The asymmetric coupling of 2-substituted 1-iodonaphthalenes and 2-substituted naphthalen-1-ylboronic acid took place in water under heterogeneous conditions in the presence of 10 mol% palladium of PS-PEG-L?-Pd complexes to give up to 94% ee of (S)-2,2′-disubstituted 1,1′-binaphthyls.
- Uozumi, Yasuhiro,Matsuura, Yutaka,Suzuka, Toshimasa,Arakawa, Takayasu,Yamada, Yoichi M. A.
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- The development of new amine-amide ligands for application in Cu(II)-catalyzed enantioselective Henry reactions
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A new type of chiral tertiary amine ligand was designed and derived from l-proline and (R)-BINOL. These new chiral ligands chelated with Cu(II) showed highly catalytic efficiency in enantioselective Henry reactions. Excellent yields (up to 99%) and high enantioselectivities (up to 96% ee) were achieved for aromatic, hetero-aromatic and aliphatic aldehyde substrates, without an additional base additive or the need for air or moisture exclusion.
- Ao, Chunyan,Men, Jian,Wang, Yang,Shao, Tao,Huang, Yuanyuan,Huo, Junji,Gao, Guowei
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p. 589 - 595
(2016/07/06)
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- Readily available catalysts for demanding Suzuki–Miyaura couplings under mild conditions
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A straightforward synthesis of a sterically hindered and electron rich bidentate monophosphine biaryl ligand Sym-Phos of C,P-type of complexation was realised in a high yield starting from simple substrates in easily affordable conditions. In combination with a palladium source, the obtained ligand formed a highly active catalyst mediating sterically demanding Suzuki–Miyaura coupling reactions in aqueous media even at 60 °C and with no need to protect the reaction mixture by an inert gas.
- Demchuk, Oleg M.,Kap?on, Katarzyna,Mazur, Liliana,Strzelecka, Dorota,Pietrusiewicz, K. Micha?
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supporting information
p. 6668 - 6677
(2016/09/28)
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- SILANE COMPOUNDS AND METHODS OF USING THEREOF
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Provided herein are silane compounds. The silane compounds can be used as organocatalysts and as sensors. Accordingly, also provided are methods of using the silane compounds described herein as catalysts. Methods of using the silane compounds described herein as catalysts can involve contacting a first organic species and a second organic species with a catalytically effective amount of a silane compound or a catalyst composition comprising a silane compound under conditions effective to form the desired product. The product can preferably be enantioenriched.
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Page/Page column 125
(2015/11/03)
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- Preparation and catalytic activity of BINOL-derived silanediols
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Enantiopure silanediols derived from BINOL are an innovative family of stereoselective hydrogen-bond donor (HBD) catalysts. Silanediols incorporated into a BINOL framework are attractive catalysts, as they are readily accessible and highly customizable. Structural modifications of the BINOL backbone affect the reactivity and selectivity of the silanediol catalysts in the additions of silyl ketene acetals to N-acyl isoquinolinium ions. The best results were obtained when the silanediol scaffold was substituted at the 4,4'- and 6,6'-positions. This report includes details regarding the properties of selected BINOL-based silanediol catalysts, including their acidities, binding constants, and X-ray crystal structures.
- Wieting, Joshua M.,Fisher, Thomas J.,Schafer, Andrew G.,Visco, Michael D.,Gallucci, Judith C.,Mattson, Anita E.
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p. 525 - 533
(2015/01/30)
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- Development of chiral bis-hydrazone ligands for the enantioselective cross-coupling reactions of aryldimethylsilanolates
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A palladium-catalyzed, enantioselective, aryl-aryl cross-coupling reaction using 1-naphthyldimethylsilanolates and chiral bis-hydrazone ligands has been developed. A family of glyoxal bis-hydrazone ligands containing various 2,5-diarylpyrrolidine groups was prepared to evaluate the influence of ligand structure on the rate and enantioselectivity of the cross-coupling. New synthetic routes to the 1-amino-2,5-diarylpyrrolidines were developed to enable the structure/reactivity-selectivity studies. Role reversal experiments of aryldimethylsilanolates and aryl bromides result in biaryl products with the same configuration and similar enantioselectivities implying that reductive elimination is the stereodetermining step. The origin of stereoselectivity is rationalized through computational modeling of diarylpalldium(II) complex which occurs through a conrotatory motion for the two aryl groups undergoing C-C bond formation.
- Denmark, Scott E.,Chang, Wen-Tau T.,Houk,Liu, Peng
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supporting information
p. 313 - 366
(2016/09/09)
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- Highly active, chemo- and enantioselective Pt-SPO catalytic systems for the synthesis of aromatic carboxamides
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Platinum complexes modified with a chiral non-racemizing SPO preligand 1 have been applied in the hydration of aromatic nitriles. [Pt(1)3Cl]Cl formed readily from Pt(COD)Cl2. The chiral secondary phosphine oxide complex showed moderate activity in the hydration of para- and meta-substituted benzonitriles, but failed in converting the ortho-substituted derivatives. The hydride complex PtH(PR2OH)(PR2O-H?OR2P) (PR2OH = 1) formed from Pt(PPh3)4 and 1, and the cationic complex derived from [Pt(1)3Cl]Cl via direct chloride abstraction with AgNO3 were proven to be considerably more active, allowing us to extend the scope to the hydration of ortho-substituted aromatic nitriles, including axially chiral [1,1′-binaphthalene]-2,2′-dicarbonitrile. In the hydration of the racemic dinitrile, successful kinetic resolution has been achieved. The catalysts derived from non-racemizing 1 are the first chiral transition metal-SPO complexes that provide kinetic resolution in the hydration of a racemic chiral nitrile.
- Gulyás, Henrik,Rivilla, Ivan,Curreli, Simona,Freixa, Zoraida,Van Leeuwen, Piet W. N. M.
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p. 3822 - 3828
(2015/07/01)
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- Dimerization of Aryl Sulfonates by in situ Generated Nickel(0)
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A mild and user-friendly nickel-catalyzed method for the reductive homocoupling of aromatic tosylates is presented. The reaction proceeds between room temperature and 60 °C, with stable substrates (ArOTs) easily prepared from inexpensive and commercially available phenols or naphthols. It relies on a catalytic amount (10 mol%) of a robust catalyst (NiBr2bipy) that does not require the preparation of sensitive organometallic intermediates. Yields are good to excellent.
- Maddaluno, Jacques,Durandetti, Muriel
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supporting information
p. 2385 - 2388
(2015/10/19)
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- 2: A highly hindered pre-catalyst for the synthesis of tetra-ortho-substituted biaryls via Grignard reagent cross-coupling
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The new well-defined catalyst [Pd(μ-Cl)Cl(IPr*)]2 enables the efficient Grignard reagent cross-coupling for the synthesis of tetra-ortho-substituted biaryls. The high reactivity of the complex is associated with the important bulkiness of the I
- Lesieur, Mathieu,Slawin, Alexandra M. Z.,Cazin, Catherine S.J.
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supporting information
p. 5586 - 5589
(2014/07/22)
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- Highly modular C1-symmetric chiral (P,N) ligands with a stereolabile P center: Experimental and theoretical studies
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An improved synthesis of a novel class of bidentate (P,N) ligands is presented, the structures of which are characterized by three distinct elements of chirality. The stereoselective installation of the elements of central chirality (at the benzylic carbon and the phosphorus atom) depends on the size of the phosphorus substituent. Thermal inversion of the phosphorus center has been studied experimentally and further correlated by DFT calculations. The potential of these ligands and the role of the phosphorus atom in the asymmetric α-arylation of aldehydes (Pd) and hydrogenation of allylic alcohols (Ir) have also been investigated. Copyright
- Humbert, Nicolas,Larionov, Evgeny,Mantilli, Luca,Nareddy, Pradeep,Besnard, Celine,Guenee, Laure,Mazet, Clement
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supporting information
p. 745 - 751
(2014/01/23)
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- Chiral silanediols in anion-binding catalysis
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A perfect pair: Silanediols are effective catalysts for the addition of silyl ketene acetals to N-acylisoquinolinium ions. Importantly, this is the first example of a silanediol plausibly participating in anion-binding catalysis, a relatively new direction in the field of hydrogen-bond-donor catalysis. The chiral, enantiopure C2-symmetric silanediol 1 catalyzes enantioselective transformations. Copyright
- Schafer, Andrew G.,Wieting, Joshua M.,Fisher, Thomas J.,Mattson, Anita E.
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supporting information
p. 11321 - 11324
(2013/11/06)
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- Synthesis and properties of macrocyclic diazene switch with binaphthalene unit attached via acrylamide linkers
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2,2′-Diiodo-1,1′-binaphthalene undergoes a tandem Heck reaction with methyl acrylate to afford methyl 2-(7H-dibenzo[c,g]fluoren-7-ylidene) acetate. As a consequence, the target macrocyclic diazene with binaphthalene unit attached via acrylamide linker was prepared by the stepwise building of acrylamide at a binaphthalene moiety, including the Doebner modification of the Knoevenagel condensation, and completed by oxidative macrocyclisation of aniline end-groups. Despite being an equimolar mixture of monomer and dimer, it exhibited remarkable changes in CD spectra due to reversible (E/Z) isomerisation of N=N diazene bonds upon irradiation at 365/465 nm. Although the dimer isomerises from (E) to (Z) isomer 7.4 times faster than the monomer, the latter's contribution to the change in ellipticity at 307 nm in the photostationary state is 2.4 times greater.
- Kickova, Anna,Kerner, Lukas,Putala, Martin,Horvath, Branislav
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p. 101 - 109,9
(2020/08/24)
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- Highly sterically hindered binaphthalene-based monophosphane ligands: Synthesis and application in stereoselective Suzuki-Miyaura reactions
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A series of new sterically hindered (R)-(2′-aryl-1,1′- binaphthalene-2-yl)phosphanes with ortho-substituted phenyls as aryl groups were prepared via Negishi monoarylation of enantiopure 2,2′-dibromo-1, 1′-binaphthalene followed by lithiation and quenching with diphenylphosphanyl or dicyclohexylphosphanyl chloride. These ligands were applied to the stereoselective Suzuki-Miyaura coupling for the preparation of substituted biaryls. The enantioselectivity correlated positively when increasing the hindrance of the 2′-aryl group of the ligand. Using the best performing diphenylphosphane ligand with a 2,6-dimethoxyphenyl aryl group, various arylnaphthalenes were prepared in high to excellent yields (68-99%) with low to good ee (12-75% ee), the latter being comparable to the best values reported when using other chiral monophosphane ligands.
- Meskova, Michaela,Putala, Martin
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p. 894 - 902
(2013/09/23)
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- Pd-catalysed asymmetric SuzukieMiyaura reactions using chiral mono- and bidentate phosphorus ligands
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A series of monodentate and bidentate chiral phosphorus based ligands including diphosphites and diphosphonites derived from carbohydrates were tested in the asymmetric Suzuki coupling of aryl halides with 2-substituted 1-naphthylboronic acids. Good activ
- Castillo, Angelica Balanta,Perandones, Bernabé F.,Zangrando, Ennio,Gladiali, Serafino,Godard, Cyril,Claver, Carmen
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supporting information
p. 31 - 36
(2013/10/08)
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- Large yet flexible N-heterocyclic carbene ligands for palladium catalysis
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A straightforward and scalable eight-step synthesis of new N-heterocyclic carbenes (NHCs) has been developed from inexpensive and readily available 2-nitro-m-xylene. This process allows for the preparation of a novel class of NHCs coined ITent ("Tent" for "tentacular") of which the well-known IMes (N,N′-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), IPr (N,N′-bis(2,6-di(2-propyl)phenyl)imidazol-2-ylidene) and IPent (N,N′-bis(2,6-di(3-pentyl)phenyl)imidazol-2-ylidene) NHCs are the simplest and already known congeners. The synthetic route was successfully used for the preparation of three members of the ITent family: IPent (N,N′-bis(2,6- di(3-pentyl)phenyl)imidazol-2-ylidene), IHept (N,N′-bis(2,6-di(4-heptyl) phenyl)imidazol-2-ylidene) and INon (N,N′-bis(2,6-di(5-nonyl)phenyl) imidazol-2-ylidene). The electronic and steric properties of each NHC were studied through the preparation of both nickel and palladium complexes. Finally the effect of these new ITent ligands in Pd-catalyzed Suzuki-Miyaura and Buchwald-Hartwig cross-couplings was investigated. Tentacular NHCs: A straightforward, scalable eight-step synthesis of N-heterocyclic carbenes (NHCs) has been developed using inexpensive and readily available 2-nitro-m-xylene, allowing the preparation of a class of NHCs designated ITent ("Tent" for "tentacular"). The electronic and steric properties of each NHC were studied through the preparation of both nickel and palladium complexes, and the effect of these new ITent ligands in Pd-catalyzed Suzuki-Miyaura and Buchwald-Hartwig cross-couplings was investigated.
- Meiries, Sebastien,Le Duc, Gaetan,Chartoire, Anthony,Collado, Alba,Speck, Klaus,Arachchige, Kasun S. Athukorala,Slawin, Alexandra M. Z.,Nolan, Steven P.
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supporting information
p. 17358 - 17368
(2014/01/06)
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- Planar chiral triazole-based phosphanes derived from [2.2]paracyclophane and their activity in suzuki coupling reactions
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In this communication we report the short synthesis of a variety of planar chiral triazole-based phosphanes. These molecules have been readily prepared from 4-azido[2.2]paracyclophane in two steps. It was observed that the stability of the resulting phosphanes was dependent on the C-4 substituent. The efficacy of the new phosphanes in the palladium-mediated Suzuki-Miyaura coupling reaction was evaluated. The phosphanes proved to be more effective than previously prepared planar chiral [2.2]paracyclophane-based phosphanes. Planar chiral phosphanes have been prepared from the first example of a [2.2]paracyclophane- derived 1,2,3-triazole with a carbon substituent at the 4-position. The nature of the 4-substituent appears to control the stability of the resulting 1,4,5-trisubstituted triazoles. The activities of the phosphanes as ligands in Suzuki coupling reactions has also been assessed. Copyright
- Glover, Jean E.,Martin, David J.,Plieger, Paul G.,Rowlands, Gareth J.
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p. 1671 - 1675
(2013/04/10)
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- Rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s: An efficient approach towards polycyclic aromatic compounds
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Ahead of the PAC: Polycyclic aromatic compounds (PACs) can be easily accessed by the combination of Suzuki-Miyaura cross-coupling and a [Rh 2(OAc)4]-catalyzed carbene reaction using easily available bis(N-tosylhydrazone)s as intermediates (see scheme; Ts=4-toluenesulfonyl). Copyright
- Xia, Ying,Liu, Zhenxing,Xiao, Qing,Qu, Peiyuan,Ge, Rui,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 5714 - 5717
(2012/07/28)
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- Atropoisomeric (P,N) ligands for the highly enantioselective Pd-catalyzed intramolecular asymmetric α-arylation of α-branched aldehydes
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Three-in-one: A short synthetic route readily gives access to a new class of chiral (P,N) ligands characterized by three distinct elements of chirality. These ligands are highly enantioselective in the challenging Pd-catalyzed intramolecular asymmetric α-
- Nareddy, Pradeep,Mantilli, Luca,Guenee, Laure,Mazet, Clement
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supporting information; scheme or table
p. 3826 - 3831
(2012/06/01)
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- [PdA (IPr*) (cinnamyl)Cl]: An efficient pre-catalyst for the preparation of tetra-ortho-substituted biaryls by Suzuki-Miyaura cross-coupling
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The bigger the better: The new well-defined [Pd(IPr*)(cin)Cl] pre-catalyst is described (see scheme). This complex proves to be highly active in the Suzuki-Miyaura cross-coupling for the synthesis of tetra-ortho- substituted biaryls under mild conditions.
- Chartoire, Anthony,Lesieur, Mathieu,Falivene, Laura,Slawin, Alexandra M. Z.,Cavallo, Luigi,Cazin, Catherine S. J.,Nolan, Steven P.
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supporting information; experimental part
p. 4517 - 4521
(2012/05/04)
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- Synthesis of tetra-ortho-substituted biaryls using aryltriolborates
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Tetra-ortho-substituted biaryls were synthesized by cross-coupling between 2,6-disubstituted bromoarenes and aryltriolborates possessing substituents at ortho carbon. The use of a copper(I) halide such as CuCl (20 mol%) with a palladium catalyst was found
- Li, Gao-Qiang,Yamamoto, Yasunori,Miyaura, Norio
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supporting information; experimental part
p. 1769 - 1773
(2011/09/12)
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- Room-temperature synthesis of tetra-ortho-substituted biaryls by NHC-catalyzed Suzuki-Miyaura couplings
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Into the groove: The introduction of a C2-symmetric N-heterocyclic carbene ligand with appropriately substituted naphthyl side chains enables the efficient Suzuki-Miyaura coupling to form bulky tetra-ortho-substituted biaryls from aryl bromides and chlorides at room temperature. DFT calculations uncover the subtle steric phenomena at play that lead to the superior catalytic performance. Cyoct=cyclooctyl. Copyright
- Wu, Linglin,Drinkel, Emma,Gaggia, Fiona,Capolicchio, Samanta,Linden, Anthony,Falivene, Laura,Cavallo, Luigi,Dorta, Reto
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p. 12886 - 12890
(2011/12/15)
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- Pushing the limits of steric demand around a biaryl axis: Synthesis of tetra-ortho-substituted biaryl naphthalenes
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The synthesis of tetra-ortho-substituted biaryl naphthalenes, including examples bearing multiple ortho-isopropyl groups, has been developed via a catalytic rearrangement process.
- Glass, Adam C.,Klonoski, Sam,Zakharov, Lev N.,Liu, Shih-Yuan
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p. 286 - 288
(2011/03/18)
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- Ferrocenyl iminophosphine ligands in Pd-catalysed Suzuki couplings
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A mixture of Pd2(dba)3/{η-C5H 4CHN[CH(CH3)(Nap)]}Fe[η-C5H 4P(tBu)2] efficiently catalyzes the Suzuki reactions of a variety of bulky aryl halides and aryl- and alkyl-boronic acids, affording the desired cross-coupling biaryl products in quantitative isolated yields under mild conditions and at low (1 × 10-6-1 mol%) Pd loadings. Spectroscopic (NMR & ESI) analysis of the mixture of Pd 2(dba)3, the hybrid [P,N] ligands, and aryl halides revealed different structural forms of oxidative addition products that are dependent on the substituent on the imino nitrogen.
- Teo, Shihui,Weng, Zhiqiang,Hor, T.S. Andy
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experimental part
p. 2928 - 2934
(2011/08/05)
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- Matching and mismatching effects of hybrid chiral biaxial bisphosphine ligands in enantioselective hydrogenation of ketoesters
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A study was conducted to demonstrate matching and mismatching of hybrid chiral biaxial bisphosphine ligands in enantioselective hydrogenation of ketoesters. A novel class of conformationally rigid Cn-TunePhos was developed by introducing a bridge with variable length to link the chiral atropisometic biaryl groups. The conformationally rigid Cn-TunePhos was introduce to investigate the synthesis and use of new chiral biophosphine ligands in asymmetric catalysis. A strategy was introduced for the synthesis of a pair of diastereoisomeric forms of ligands 1, 2, and an analogous ligand 3 to assess the effects of stereochemical matching and mismatching interactions upon the structural and catalytic properties of the corresponding ruthenium complexes. Their applications in highly efficient Ru-catalyzed asymmetric hydrogenation for the enantioselective synthesis of α- and β-hydroxy acid derivatives were also explored.
- Sun, Xianfeng,Li, Wei,Zhou, Le,Zhang, Xumu
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supporting information; experimental part
p. 7302 - 7305
(2010/03/24)
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- Binaphthalene-derived iminium salt catalysts for highly enantioselective asymmetrie epoxidation
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Enantiomerically enriched epoxides are useful intermediates that have found many applications in asymmetric synthesis, and development of efficient catalysts for asymmetric epoxidation has received considerable attention, In this manuscript we describe the design, preparation, and use of new highly selective imlnium salt organocatalysts for asymmetric epoxidation, based around a chiral binaphthalene motif coupled with a chiral substituted dioxane moiety. The new catalysts have been tested in the catalytic asymmetric epoxidation of unfunctionalized alkenes, and provide up to 95 % ee.
- Bulman Page, Philip C.,Buckley, Benjamin R.,Farah, Mohamed M.,John Blacker
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experimental part
p. 3413 - 3426
(2011/02/26)
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- Highly active, well-defined (cyclopentadiene)(N-heterocyclic carbene)palladium chloride complexes for room-temperature Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions of aryl chlorides and deboronation homocoupling of arylboronic acids
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A new class of well-defined N-heterocyclic carbene (NHC)-(cyclopentadiene) palladium chloride complexes such as CpPd(NHC)Cl wasw synthesized from the readily available starting NHC-palladium(II) chloride dimers. These air-stable, coordinatively saturated NHC-Pd complexes bearing the cyclopentadiene (Cp) unit exhibit high catalytic activity in the room temperature Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions involving unactive aryl chlorides as the substrates. In addition, they are found to be extremely efficient catalysts in the deboronation homocoupling of arylboronic acids at room temperature.
- Jin, Zhong,Guo, Su-Xian,Gu, Xiao-Peng,Qiu, Ling-Ling,Song, Hai-Bing,Fang, Jian-Xin
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supporting information; experimental part
p. 1575 - 1585
(2011/02/28)
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- New chiral binaphthalene-derived iminium salt organocatalysts for asymmetric epoxidation of alkenes
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(Chemical Equation Presented) A series of binaphthalene-fused azepinium salts has been generated and used as organocatalysts in the asymmetric epoxidation of unfunctionalized alkenes, giving rise to ees of up to 84%.
- Page, Philip C. Bulman,Farah, Mohamed M.,Buckley, Benjamin R.,Blacker, A. John
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p. 4424 - 4430
(2008/02/05)
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- Enantioselective hydrogenation with self-assembling rhodium phosphene catalysts: Influence of ligand structure and solvent
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Three sets of new and related chiral phospholane and phosphepine ligands have been prepared for Rh-catalyzed enantioselective hydrogenation. The size and substitution pattern of the cyclic monophosphanes were varied. More importantly, the ligands differ in the nature of the heterocyclic group linked to the trivalent phosphorus atom: 2-pyridone or 2-alkoxypyridine. In the corresponding Rh complexes, the pyridone units of two monodentate P ligands can assemble by hydrogen bonding and form chelates. In contrast, synthetic precursors bearing alkoxypyridine appendages are not able to aggregate via intramolecular hydrogen bonds. The nature of self-assembly is dependent on the nature of the P ligand and the solvent used for the hydrogenation (CH 2Cl2 vs. MeOH). These features affect the rate of the reaction as well as the enantioselectivity, which varied in the range of 0-99 % ee Complexation studies and DFT calculations were performed to explain these differences.
- Birkholz, Mandy-Nicole,Dubrovina, Natalia V.,Jiao, Haijun,Michalik, Dirk,Holz, Jens,Paciello, Rocco,Breit, Bernhard,Boerner, Armin
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p. 5896 - 5907
(2008/02/13)
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- Microwave assisted asymmetric Suzuki-Miyaura and Negishi cross-coupling reactions: synthesis of chiral binaphthalenes
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Microwave assisted asymmetric Suzuki-Miyaura and Negishi enantioselective cross-coupling reactions are reported for the first time, and have been applied to the rapid synthesis of chiral sterically hindered binaphthalene derivatives in reasonable to excellent yields (65-96%) and fair to good enantioselectivities (43-70% ee).
- Genov, Miroslav,Almorin, Antonio,Espinet, Pablo
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p. 625 - 627
(2007/10/03)
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- Efficient synthesis of chiral 1,1′-binaphthalenes by the asymmetric suzuki-miyaura reaction: Dramatic synthetic improvement by simple purification of naphthylboronic acids
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Naphthylboronic acids prepared as reported in the literature are contaminated with HCl. A very simple purification prior to their use in Suzuki-Miyaura couplings has been found to be crucial, rendering efficient some reactions that had been reported in th
- Genov, Miroslav,Almorin, Antonio,Espinet, Pablo
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p. 9346 - 9352
(2007/10/03)
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- OPTICALLY ACTIVE QUATERNARY AMMONIUM SALT HAVING AXIAL ASYMMETRY AND PROCESS FOR PRODUCING ALPHA-AMINO ACID AND DERIVATIVE THEREOF WITH THE SAME
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The present invention provides a compound of the following formula (I) below. This compound (I) can be produced by reacting a 2,2'-dimethylene bromide-1,1'-binaphthyl derivative, which can be produced by a relatively small number of processes, with an eas
- -
-
Page/Page column 62-63
(2008/06/13)
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- Reductive ring opening of dihydrodibenzothiepine and dihydrodinaphtho- oxepine and -thiepine
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The 4,4′di-tert-butylbiphenyl (DTBB)-catalysed lithiation of dihydrodibenzothiepine (1) at -78°C for 30 min followed by reaction with a carbonyl compound [tBuCHO, Ph(CH2)2CHO, PhCHO, (n-C5H11)2/
- Foubelo, Francisco,Moreno, Benjamín,Soler, Tatiana,Yus, Miguel
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p. 9082 - 9096
(2007/10/03)
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- PROCESS FOR USE IN THE PREPARATION OF OXIRANES FROM ALKENES, AND CATALYSTS FOR USE THEREIN
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There is provided a process for the preparation of oxiranes wherein an optionally substituted alkene is reacted in the presence of a chiral catalyst, an oxidant and an organic solvent characterised in that the oxidant is at least partially soluble in the organic solvent and the oxidant displays low reactivity towards the alkene in the absence of the catalyst. The optionally substituted alkene is preferably an alkene of formula (1): wherein: R1-4 each independently are hydrogen, an optionally substituted aromatic or is saturated hydrocarbyl, an optionally substituted hetrocyclyl, an optionally substituted aromatic or saturated hydrocarbyloxy, an optionally substituted aromatic or saturated hydrocarbylamino, an optionally substituted aromatic or saturated hydrocarbyloxycarbonyl, an optionally substituted aromatic or saturated hydrocarbylaminocarbonyl, nitrile, halide or one or more of R1& R2, R2& R3 , R3& R4 , R1& R4 optionally being linked in such a way as to form an optionally substituted ring(s). The oxidant is preferably an oxidant of formula (2): A+ HSO5- wherein A+ is a counterion capable of conferring organic solvent solubility. Preferred chiral catalysts of formula (4): wherein: R11 and R12 are each independently an optionally substituted hydrocarbyl group or R11& R12 are linked in such a way as to form an optionally substituted ring(s); R13 is hydrogen or an optionally substituted hydrocarbyl group; R14 is an optionally substituted hydrocarbyl group; R17 is hydrogen or an optionally substituted hydrocarbyl group; R15 and R16 each independently are hydrogen or an optionally substituted hydrocarbyl group; and 30 X- is a counterion; * is a chiral centre; and *' is a chiral centre when R17 is not hydrogen are provided.
- -
-
Page/Page column 17
(2010/02/12)
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- Short and efficient synthesis of coronene derivatives via ruthenium-catalyzed benzannulation protocol
-
TpRuPPh3(CH3CN)2PF6 (3 mol %) was very active in catalytic benzannulation of 1-phenyl-2-ethynylbenzenes in dichloroethane (60 °C, 36 h) to afford phenanthrene in 95% yield. This method is applicable to the synthesis of various polycyclic aromatic hydrocarbons via two- and four-fold benzannulations, including various substituted coronene derivatives (53-86% yields) using this catalyst at a moderate loading (10 mol %).
- Shen, Hung-Chin,Tang, Jhih-Meng,Chang, Hsu-Kai,Yang, Chia-Wei,Liu, Rai-Shung
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p. 10113 - 10116
(2007/10/03)
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- Iron-catalyzed oxidative homo-coupling of aryl grignard reagents
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(Chemical Equation Presented) Iron-catalyzed homo-coupling of aryl Grignard reagents was successfully developed. A variety of aryl Grignard reagents were efficiently converted into the corresponding symmetrical biaryls in the presence of 1-5 mol % FeCl3 and a stoichiometric amount of 1,2-dichloroethane.
- Nagano, Takashi,Hayashi, Tamio
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p. 491 - 493
(2007/10/03)
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