- Rapid Access to Highly Functionalized Alkyl Boronates by NiH-Catalyzed Remote Hydroarylation of Boron-Containing Alkenes
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The direct and selective functionalization of relatively simple and readily accessible precursors to produce highly functionalized alkyl boronates is a synthetically useful process. Herein we report a NiH-catalyzed remote hydroarylation process that can, through a synergistic combination of chain walking and subsequent cross-coupling, introduce an aryl group at the adjacent carbon atom of alkyl boronates under mild conditions. By means of a preliminary experiment with moderate enantioselectivity, it was shown that an asymmetric version could also be realized.
- Zhang, Yao,Han, Bo,Zhu, Shaolin
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supporting information
p. 13860 - 13864
(2019/08/08)
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- A Tunable Route to Prepare α,β-Unsaturated Esters and α,β-Unsaturated-γ-Keto Esters through Copper-Catalyzed Coupling of Alkenyl Boronic Acids with Phosphorus Ylides
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A tunable strategy to prepare α,β-unsaturated esters and α,β-unsaturated-γ-keto esters in good to excellent yields was developed through copper-catalyzed oxidative coupling of phosphorus ylides with alkenyl boronic acids under mild conditions. The reaction without water afforded α,β-unsaturated esters, ketones, and amides while α,β-unsaturated-γ-keto esters, 1,4-α,β-unsaturated diketones and α,β-unsaturated-γ-keto amides were obtained when using 5.0 equiv. of water. H2O18 labeling experiments showed that water played an important role in the formation of α,β-unsaturated-γ-keto esters. A plausible formation mechanism for α,β-unsaturated esters and α,β-unsaturated-γ-keto esters was proposed based on mechanistic studies. Phosphonium salts could also be used directly as coupling partners instead of phosphorus ylides. The reaction exhibited a broad substrate scope, good functional group tolerance, good regioselectivity, and diverse coupling products. (Figure presented.).
- Bi, Hong-Yan,Liu, Feng-Ping,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
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supporting information
p. 1510 - 1516
(2018/03/05)
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- Regioselectivity of 1,3-Dipolar Cycloadditions of Benzonitrile Oxide to Alkenyl Boronic Esters: An Experimental and Computational Study
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1,3-Dipolar cycloaddition reactions of benzonitrile oxide to monosubstituted or 1,1-disubstituted alkenyl boronic ester gave only 2-isoxazolines, bearing the boronic ester group at the 5-position of the ring. On the other hand, the cycloaddition reactions of benzonitrile oxide with trans-1,2-disubstituted alkenyl boronic esters produced 2-isoxazolines, bearing the boronic ester group at the 4-position of the ring. We used quantum mechanical calculations to investigate two regioisomeric channels that were associated with the formation of 2-isoxazolines, bearing the boronic ester group at the 4-position or 5-position. The study revealed that the experimental results agreed well with the parameters based on the transition state energies in gas or solvent phase. The study also informed that all the cycloaddition reactions proceed in a spontaneous and exergonic fashion.
- Jeong, Jo,Zong, Kyukwan,Choe, Joong Chul
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p. 1007 - 1014
(2017/03/27)
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- ASYMMETRIC ADDITION REACTIONS
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Processes of forming Csp2-Csp3 bonds at the allylic carbon of a cyclic allylic compound starting material are disclosed, in which a racemic mixture of a cyclic allylic compound having a leaving group attached to the allylic carbon is reacted with a compound having a nucleophilic carbon atom in the presence of a Rh(l), Pd(ll) or Cu(l) pre-catalyst and a chiral ligand. The reaction products containing the newly-formed Csp2-Csp3 bond are generated in high stereoisomeric excess, and may therefore serve as important organic building blocks in the preparation of new agrochemicals and pharmaceuticals.
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Paragraph 00134
(2016/12/26)
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- N-B dative bond-induced [3.3.0] bicyclic boronate-tethered exo-selective intramolecular Diels-Alder reaction
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We report herein a highly exo-selective intramolecular Diels-Alder reaction of alkenyl boronates which employs an N-B dative bond-involved bicyclic rigid tether. Complex C(sp3)-rich polycyclic molecules containing up to 8 stereocenters can be readily formed via an operationally simple two-step procedure.
- Feng, Chao,Wang, Hong,Xu, Liang,Li, Pengfei
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supporting information
p. 7136 - 7139
(2015/07/01)
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- Liebeskind-Srogl cross-coupling on γ-carboxyl-γ-butyrolactone derivatives: Application to the side chain of amphidinolides C and F
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The synthetic approach for the C20-C29 and C20-C34 fragments of amphidinolide F and C was based on an original Liebeskind-Srogl cross-coupling reaction with a glutamic acid-derived building-block. Further highly diastereoselective reduction of the ketone was achieved by using an uncommon Ph3SiH/TBAF/HMPA system. The amphidinolide C side chain was built through a reductive elimination of chiral epoxide to install the stereogenic center at C29.
- Fenneteau, Johan,Vallerotto, Sara,Ferrié, Laurent,Figadère, Bruno
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supporting information
p. 3758 - 3761
(2015/06/08)
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- Microwave-assisted Suzuki-Miyaura cross-coupling of 2-alkyl and 2-alkenyl-benzo-1,3,2-diazaborolanes
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Nitrogen-based boronate esters, such as 2-octyl-benzo-1,3,2-diazaborolane, 2-phenethyl-benzo-1,3,2-diazaborolane, and 2-{(1E)-hexenyl}-benzo-1,3,2- diazaborolane have been shown to be suitable coupling partners with arylhalides in microwave accelerated Suzuki cross-coupling reactions. Reaction yields of up to 89% were achieved. The use of a silicon group attached to the nitrogen atom, proved to enhance the reactivity of 2-octyl-benzo-1,3,2-diazaborolane.
- Hadebe, Siphamandla W.,Sithebe, Siphamandla,Robinson, Ross S.
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scheme or table
p. 4277 - 4282
(2011/06/26)
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- A convenient catalyst for aqueous and protein Suzuki-Miyaura cross-coupling
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(Figure Presented) A phosphine-free palladium catalyst for aqueous Suzuki-Miyaura cross-coupling is presented. The catalyst is active enough to mediate hindered, ortho-substituted biaryl couplings but mild enough for use on peptides and proteins. The Suzuki-Miyaura couplings on protein substrates are the first to proceed in useful conversions. Notably, hydrophobic aryl and vinyl groups can be transferred to the protein surface without the aid of organic solvent since the aryl- and vinylboronic acids used in the coupling are water-soluble as borate salts. The convenience and activity of this catalyst prompts use in both general synthesis and bioconjugation.
- Chalker, Justin M.,Wood, Charlotte S. C.,Davis, Benjamin G.
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supporting information; experimental part
p. 16346 - 16347
(2010/01/29)
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- Facile synthesis of iodonium salts by reaction of organotrifluoroborates with p-iodotoluene difluoride
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A simple and easy method for the synthesis of various iodonium salts was developed, and involves the reaction of potassium organotrifluoroborates with p-iodotoluene difluoride under mild conditions. The one-pot synthesis of a (Z)-(2-fluoroalkenyl)iodonium
- Yoshida, Masanori,Osafune, Kanako,Hara, Shoji
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p. 1542 - 1546
(2008/02/05)
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- Synthesis and biological evaluation of 6,7-disubstituted 4-aminopyrido[2,3-d]pyrimidines as adenosine kinase inhibitors
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The synthesis and structure-activity relationship of a series of 6,7-disubstituted 4-aminopyrido[2,3-d]pyrimidines as novel non-nucleoside adenosine kinase inhibitors is described. A variety of substituents, primarily aryl, at the C6 and C7 positions of the pyridopyrimidine core were found to yield analogues that are potent inhibitors of adenosine kinase. In contrast to the 5,7-disubstituted and 5,6,7-trisubstituted pyridopyrimidine series, these analogues exhibited only modest potency to inhibit AK in intact cells.
- Perner, Richard J.,Lee, Chih-Hung,Jiang, Meiqun,Gu, Yu-Gui,DiDomenico, Stanley,Bayburt, Erol K.,Alexander, Karen M.,Kohlhaas, Kathy L.,Jarvis, Michael F.,Kowaluk, Elizabeth L.,Bhagwat, Shripad S.
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p. 2803 - 2807
(2007/10/03)
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- 2-Pyrones possessing antimicrobial and cytotoxic activities
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The 2-pyrone sub-unit is found in a number of natural products possessing broad spectrum biological activity. Such compounds are validated as being capable of binding to specific protein domains and able to exert a remarkable range of biological effects. In an effort to identify synthetic 2-pyrones with interesting biological effects, herein we report the synthesis and biological evaluation of 4-substituted-6-methyl-2-pyrones. Synthetic routes to 4-alkyl/alkenyl/aryl/alkynyl-6-methyl-2-pyrones have been developed utilising Sonogashira, Suzuki and Negishi cross-coupling starting from readily available 4-bromo-6-methyl-2-pyrone. Specific conditions for each organometallic protocol were required for successful cross-coupling. In particular, a triethylamine/acetonitrile - base/solvent mixture was crucial to Sonogashira alkynylation of 4-bromo-6-methyl-2-pyrone, whereas thallium carbonate was a mandatory base for the Suzuki cross-coupling of trialkylboranes. The 2-pyrones demonstrate potent inhibitory activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Schizosaccharomyces pombe and Botrytis cinerea. The growth inhibitory activities of selected 2-pyrones were determined in A2780 human ovarian carcinoma and K562 human chronic myelogenous leukaemia cell lines using an in vitro cell culture system (MTT assay). These studies demonstrate that 4-phenylethynyl-, 4-tetrahydropyranylpropargyl ether- and 4-ethynyl-6-methyl-2-pyrones have excellent potential as a new class of anticancer agents.
- Fairlamb, Ian J. S.,Marrison, Lester R.,Dickinson, Julia M.,Lu, Feng-Ju,Schmidt, Jan Peter
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p. 4285 - 4299
(2007/10/03)
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- Dichloroborane-dioxane: An exceptional reagent for the preparation of alkenyl- and alkylboronic acids
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Terminal alkynes and alkenes were conveniently hydroborated to the corresponding alkenyl- and alkyldichloroboranes using dichloroborane-dioxane in dichloromethane. These dichloroboranes were hydrolyzed by water to the corresponding alkenyl- and alkylboron
- Josyula, Kanth V. B.,Gao, Peng,Hewitt, Chris
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p. 7789 - 7792
(2007/10/03)
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- Palladium catalysed tandem cyclisation-anion capture. Part 8: Cascade hydrostannylation-cyclisation-anion capture and cascade hydroboration-cyclisation-anion capture on solid phase
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Up to four bonds and five stereocentres are created, in five component processes (five point diversity), utilising resin bound aryl iodides by hydroboration or hydrostannylation of alkynes, followed by cyclisation-anion capture involving Suzuki or Stille reactions. Three small libraries were prepared to validate the chemistry.
- Grigg, Ronald,MacLachlan, William S,MacPherson, David T,Sridharan, Visuvanathar,Suganthan, Selvaratnam
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p. 10335 - 10345
(2007/10/03)
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- Potassium alkenyl- and aryltrifluoroborates: Stable and efficient agents for rhodium-catalyzed addition to aldehydes and enones
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(matrix presented). Potassium alkenyl- and aryltrifluoroborates undergo addition to enones and aldehydes in the presence of Rh(I) catalysts to give β-functionalized ketones and allylic/benzylic alcohols, respectively. Reaction proceeds more rapidly than with the corresponding boronic acids, and the choice of phosphine ligand does not signifcantly influence the overall efficiency of addition.
- Batey, Robert A.,Thadani, Avinash N.,Smil, David V.
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p. 1683 - 1686
(2008/02/09)
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- H NMR evidence for the formation of vinyllead triacetates. The reactions of vinylmercury, vinyltin, and vinylboronic acids with lead tetraacetate
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Vinylmercury compounds, vinylboronic acids and vinylstannanes undergo rapid metal-lead exchange with lead tetraacetate in deuterochloroform to generate vinyllead triacetates, which have been characterised by their 1H-1H and 207Pb-1H coupling constants. In addition, a number of divinyl and mixed aryl-vinyllead dicarboxylates have been prepared via boron-lead exchange.
- Parkinson, Christopher J.,Stoermer, Martin J.
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p. 207 - 214
(2007/10/03)
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