- Electro-Olefination—A Catalyst Free Stereoconvergent Strategy for the Functionalization of Alkenes
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Conventional methods carrying out C(sp2)?C(sp2) bond formations are typically mediated by transition-metal-based catalysts. Herein, we conceptualize a complementary avenue to access such bonds by exploiting the potential of electrochemistry in combination with organoboron chemistry. We demonstrate a transition metal catalyst-free electrocoupling between (hetero)aryls and alkenes through readily available alkenyl-tri(hetero)aryl borate salts (ATBs) in a stereoconvergent fashion. This unprecedented transformation was investigated theoretically and experimentally and led to a library of functionalized alkenes. The concept was then carried further and applied to the synthesis of the natural product pinosylvin and the derivatization of the steroidal dehydroepiandrosterone (DHEA) scaffold.
- Baumann, Andreas N.,Dechent, Jonas,Didier, Dorian,Jagau, Thomas C.,Müller, Nicolas,Music, Arif
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supporting information
(2020/07/04)
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- Palladium-catalyzed B-diarylation of diethylaminoborane for the synthesis of diarylborinic acids
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The palladium-catalyzed synthesis of diarylborinic acid derivatives by intermolecular cross-coupling between aryl iodides and (amino)dihydrideborane is reported. The key to success of the reaction is the use of a less bulky diethylaminoborane reagent, which facilitates the second B-arylation.
- Igarashi, Takuya,Shimazumi, Ryoma,Tobisu, Mamoru
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supporting information
p. 760 - 763
(2020/07/10)
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- Electrochemical Synthesis of Biaryls via Oxidative Intramolecular Coupling of Tetra(hetero)arylborates
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We report herein versatile, transition metal-free and additive-free (hetero)aryl-aryl coupling reactions promoted by the oxidative electrocoupling of unsymmetrical tetra(hetero)arylborates (TABs) prepared from ligand-exchange reactions on potassium trifluoroarylborates. Exploiting the power of electrochemical oxidations, this method complements the existing organoboron toolbox. We demonstrate the broad scope, scalability, and robustness of this unconventional catalyst-free transformation, leading to functionalized biaryls and ultimately furnishing drug-like small molecules, as well as late stage derivatization of natural compounds. In addition, the observed selectivity of the oxidative coupling reaction is related to the electronic structure of the TABs through quantum-chemical calculations and experimental investigations.
- Music, Arif,Baumann, Andreas N.,Spie?, Philipp,Plantefol, Allan,Jagau, Thomas C.,Didier, Dorian
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supporting information
p. 4341 - 4348
(2020/03/04)
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- Borinic Acids via Direct Arylation of Amine-Borane Complexes: An Air- and Water-Stable Boron Source
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A synthesis of borinic acids and borinates was optimized using amine-borane complexes as a water and air insensitive borylating agent. The reaction operates under convenient conditions using a non-cryogenic temperature and with no flash chromatography, and it gives no boron impurities. The reaction proceeds through a tandem dehydrogenation-double addition mechanism.
- Richard, Jimmy,Birepinte, Mélodie,Charbonnier, Jean Baptiste,Liautard, Virginie,Pinet, Sandra,Pucheault, Mathieu
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p. 736 - 744
(2017/02/15)
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- Borinic acid catalysed peptide synthesis
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The catalytic synthesis of peptides is a major challenge in the modern organic chemistry hindered by the well-established use of stoichiometric coupling reagents. Herein, we describe for the first time that borinic acid is able to catalyse this reaction under mild conditions with an improved activity compared to our recently developed thiophene-based boronic acid. This catalyst is particularly efficient for peptide bond synthesis affording dipeptides in good yields without detectable racemization.
- El Dine, Tharwat Mohy,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 16084 - 16087
(2015/11/10)
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- Design, synthesis and pharmacological characterization of analogs of 2-aminoethyl diphenylborinate (2-APB), a known store-operated calcium channel blocker, for inhibition of TRPV6-mediated calcium transport
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2-Aminoethyl diphenylborinate (2-APB) is a known modulator of the IP 3 receptor, the calcium ATPase SERCA, the calcium release-activated calcium channel Orai and TRP channels. More recently, it was shown that 2-APB is an efficient inhibitor of the epithelial calcium channel TRPV6 which is overexpressed in prostate cancer. We have conducted a structure-activity relationship study of 2-APB congeners to understand their inhibitory mode of action on TRPV6. Whereas modifying the aminoethyl moiety did not significantly change TRPV6 inhibition, substitution of the phenyl rings of 2-APB did. Our data show that the diaryl borinate moiety is required for biological activity and that the substitution pattern of the aryl rings can influence TRPV6 versus SOCE inhibition. We have also discovered that 2-APB is hydrolyzed and transesterified within minutes in solution.
- Hofer, Alexandre,Kovacs, Gergely,Zappatini, Anna,Leuenberger, Michele,Hediger, Matthias A.,Lochner, Martin
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p. 3202 - 3213
(2013/07/11)
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- Cross-coupling of diarylborinic acids and anhydrides with arylhalides catalyzed by a phosphite/N-heterocyclic carbene co-supported palladium catalyst system
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A highly efficient cross-coupling of diarylborinic acids and anhydrides with aryl chlorides and bromides has been effected by using a palladium catalyst system co-supported by a strong σ-donor N-heterocyclic carbene (NHC), N,N′-bis(2,6-diisopropylphenyl) imidazol-2-ylidene, and a strong π-acceptor phosphite, triphenylphosphite, in tert-BuOH in the present of K3PO4·3H2O. Unsymmetrical biaryls with a variety of functional groups could be obtained in good to excellent yields using as low as 0.01, 0.2-0.5, and 1 mol % palladium loadings for aryl bromides and activated and deactivated aryl chlorides, respectively, under mild conditions. A ligand synergy between the σ-donor NHC and the π-acceptor phosphite in the Pd/NHC/P(OPh)3 catalytic system has been proposed to be responsible for the high efficacy to arylchlorides in the cross-coupling. A scalable and economical process has therefore been developed for synthesis of Sartan biphenyl from the Pd/NHC/P(OPh)3 catalyzed cross-coupling of di(4-methylphenyl)borinic acid with 2-chlorobenzonitrile.
- Chen, Xiaofeng,Ke, Haihua,Chen, Yao,Guan, Changwei,Zou, Gang
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p. 7572 - 7578
(2012/10/29)
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- Treatment of bacterial induced diseases using DNA methyl transferase inhibitors
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Methods for treating and/or preventing disease conditions caused or induced or aggravated by microbes, especially bacteria, by inhibiting DNA methyltransferase activity, such as by administering to an animal a DNA methyltransferase inhibitor, are disclosed, along with methods of reducing or ablating virulence in bacteria by inhibiting DNA methyltransferase activity.
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Page/Page column 31-32
(2008/06/13)
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- Identification of borinic esters as inhibitors of bacterial cell growth and bacterial methyltransferases, CcrM and MenH
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As bacteria continue to develop resistance toward current antibiotics, we find ourselves in a continual battle to identify new antibacterial agents and targets. We report herein a class of boron-containing compounds termed borinic esters that have broad spectrum antibacterial activity with minimum inhibitory concentrations (MIC) in the low microgram/mL range. These compounds were identified by screening for inhibitors against Caulobacter crescentus CcrM, an essential DNA methyltransferase from Gram negative α-proteobacteria. In addition, we demonstrate that borinic esters inhibit menaquinone methyltransferase in Gram positive bacteria using a new biochemical assay for MenH from Bacillus subtilis. Our data demonstrate the potential for further development of borinic esters as antibacterial agents as well as leads to explore more specific inhibitors against two essential bacterial enzymes.
- Benkovic, Stephen J.,Baker, Stephen J.,Alley,Woo, Youn-Hi,Zhang, Yong-Kang,Akama, Tsutomu,Mao, Weimin,Baboval, Justin,Rajagopalan, P. T. Ravi,Wall, Mark,Kahng, Lyn Sue,Tavassoli, Ali,Shapiro, Lucy
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p. 7468 - 7476
(2007/10/03)
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- DNA Methyltransferase inhibitors
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A compound of the formula or a pharmaceutically acceptable salt thereof,whereinR1, R2, and R3 are the same or different and are independently hydrogen, lower alkyl, aryl or substituted aryl, lower alkoxy, lower alkoxyalkyl, or cycloalkyl or cycloalkyl alkoxy, where each cycloalkyl group has from 3-7 members, where up to two of the cycloalkyl members are optionally hetero atoms selected from oxygen and nitrogen, and where any member of the alkyl, aryl or cycloalkyl group is optionally substituted with halogen, lower alkyl or lower alkoxy, aryl or substituted aryl, andwhereR3 can be ribose, deoxyribose or phosphorylated derivatives thereof,whereinR1, R2, and R3 are not all hydrogen andwhereinwhen R3 is ribose, deoxyribose or phosphorylated derivatives thereof, one of R1 or R2 is not hydrogen.
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- Palladium-catalyzed cross-coupling reaction of potassium diaryldifluoroborates with aryl halides
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The catalytic cross-coupling reaction of potassium diaryldifluoroborates with aryl halides proceeds to afford the biphenyls in good yields. These salts on an arylation reagent were readily prepared via a protocol of the Grignard method and transformation to potassium salts. Two aryl groups of these salts were efficiently transferred in the Suzuki-Miyaura reaction.
- Ito, Takatoshi,Iwai, Toshiyuki,Mizuno, Takumi,Ishino, Yoshio
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p. 1435 - 1438
(2007/10/03)
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