- A study of the effect on nucleophilic hydrolytic activity of pancreatic elastase, trypsin, chymotrypsin, and leucine aminopeptidase by boronic acids in the presence of arabinogalactan: A subsequent study on the hydrolytic activity of chymotrypsin by boronic acids in the presence of mono-, di-, and trisaccharides
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The hydrolytic activity of trypsin, chymotrypsin, elastase, and leucine aminopeptidase, is inhibited by different boronic acids. However, all the enzymes are inhibited by the compound CbzAla(boro)Gly(OH)2. Therefore, these additives can control the nucleophilic hydrolytic activity of these enzymes.
- Smoum, Reem,Rubinstein, Abraham,Srebnik, Morris
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Read Online
- Synthesis and stability of new spiroaminoborate esters
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New spiroaminoborate esters derived from 1,1-diphenylprolinol, ephedrine, and dihydroquinine with different alkoxy substituents were prepared as stable crystalline compounds and characterized by spectroscopical analysis and specific rotation. The structure of the spiroborate 4 derived from 1,1-diphenylprolinol and dicyclohexyl-1,1′-diol was confirmed by X-ray analysis.
- Stepanenko, Viatcheslav,De Jesús, Melvin,Garcia, Carmelo,Barnes, Charles L.,Ortiz-Marciales, Margarita
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Read Online
- Hydroboration of nitriles, esters, and amides catalyzed by simple neosilyllithium
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We present here an efficient method for the hydroboration of organic nitriles, carboxylic esters, and carboxamides with pinacolborane (HBpin) using an alkali metal catalyst, neosilyllithium (LiCH2SiMe3), in neat reaction conditions. The reactions were accomplished with efficient catalytic reactivity and demonstrated by neosilyllithium at room temperature, in solvent-free condition, to afford a high yield of the corresponding N-boryl amines, boryl ethers, and amine hydrochlorides. The protocol for the catalytic reaction presented in this paper is simple and efficient, with diverse substrate scope for nitriles, carboxylic esters, and carboxamides showing excellent functional group tolerance. DLPNO-CCSD(T) calculations were also performed, showing that the hydroboration of nitriles catalyzed by neosilyllithium occurs through the pre-coordination of the nitrile at Lewis acid lithium followed by hydride migration from the B–H entity.
- Bandyopadhyay, Ayan,Bhattacharjee, Jayeeta,Kumar Singh, Saurabh,Kumari, Kusum,Moorthy, Shruti,Panda, Tarun K.,Sai Kumar, Gobbilla
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supporting information
(2022/03/31)
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- Catalytic hydroboration of carbonyl derivatives by using phosphinimino amide ligated magnesium complexes
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Reduction of carbonyl derivatives by using Earth-abundant, cheap, and environmentally benign metal-based catalysts through an atom-efficient method is a challenging task. Herein, we report the synthesis and characterization of dinuclear magnesium complexes 1-3 chelated by a phosphinimino amide skeleton. In combination with pinacolborane (HBpin) as a reducing agent, complex 1 bearing an ortho-methyl substituent on the phenyl ring of the ligand showed excellent reduction capability for a broad range of carbonyl derivatives under mild reaction conditions. Aldehydes, ketones, and acrolein substrates were efficiently reduced to the corresponding alkoxy-borane products with a record high TOF. Besides, acrolein derivatives were exclusively reduced to 1,2-regioselective products. Using two equiv. of HBpin, ester substrates were reduced to two kinds of alkoxy-borane products. Carbonate reduction accomplished by using complex 1 and three equiv. of HBpin afforded diols and a methanol precursor, respectively. When chiral substrates such as (S)-1,2-propanediol carbonate and l-lactide or polymeric P(l-LA) were employed, the chirality was almost retained in their reductive products.
- Cui, Dongmei,Li, Min,Liu, Xinli
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supporting information
p. 13037 - 13041
(2021/10/12)
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- Hydroboration of aldehydes, ketones and CO2under mild conditions mediated by iron(iii) salen complexes
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The hydroboration of aldehydes, ketones and CO2is demonstrated using a cheap and air stable [Fe(salen)]2-μ-oxo pre-catalyst with pinacolborane (HBpin) as the reductant under mild conditions. This catalyst system chemoselectively hydroborates aldehydes over ketones and ketones over alkenes. In addition, the [Fe(salen)2]-μ-oxo pre-catalyst shows good efficacy at reducing “wet” CO2with HBpin at room temperature.
- James, Alexander P.,Lau, Samantha,Provis-Evans, Cei B.,Webster, Ruth L.
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supporting information
p. 10696 - 10700
(2021/08/17)
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- Nucleophilic Addition and α-C-H Substitution Reactions of an Imine Mediated by Dibutylmagnesium and Organolithium Reagents
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A series of nucleophilic addition reactions and α-C-H substitution reactions of an imine-containing ligand 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine (HL1) were reported. The reactions of HL1 with 0.5 and 2 equiv ofnBu2Mg, respectively, gave two complexes of compositions [Mg(L1)2] (1) and [Mg2(L2)2] (2) (H2L2 =N-((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)pentan-1-amine). The nucleophilic addition ofnBu2Mg to the C═N bond of the HL1 ligand occurred in the process for the formation of2. Treatment of HL1 with 2 and 1 equiv ofnBuLi generated [Li2(L3)2] (3) (HL3 = 2-(2-(((1-(1H-pyrrol-2-yl)pentylidene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine) and [Li2(L1)2] (4). An α-C-H substitution of the HC═NR moiety of the HL1 ligand triggered bynBuLi was discovered in the preparation of3. The formation of3demonstrates a new concept for the C-C coupling that involved inert C-H bond activation of HC═NR skeleton. The reactions of HL1 with MeLi,sec-BuLi, and tert-BuLi, respectively, were also examined. The products for both the nucleophilic addition of organolithium reagents to the C═N bond and α-C-H substitution of the HC═NR moiety of the HL1 ligand were determined. The mechanisms for the formations of2and3were rationalized by DFT calculations. The hydroboration reactions catalyzed by2were investigated, and these reactions characterize ample substrate scope, very good yields, and high selectivity.
- Dang, Yan,Jia, Chaohong,Li, Yafei,Li, Yahong,Lu, Yanhua,Wang, Yalan,Xia, Yuanzhi,Xu, Man,Zhang, Liang
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- Metal–Ligand Cooperativity of the Calix[4]pyrrolato Aluminate: Triggerable C?C Bond Formation and Rate Control in Catalysis
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Metal-ligand cooperativity (MLC) had a remarkable impact on transition metal chemistry and catalysis. By use of the calix[4]pyrrolato aluminate, [1]?, which features a square-planar AlIII, we transfer this concept into the p-block and fully elucidate its mechanisms by experiment and theory. Complementary to transition metal-based MLC (aromatization upon substrate binding), substrate binding in [1]? occurs by dearomatization of the ligand. The aluminate trapps carbonyls by the formation of C?C and Al?O bonds, but the products maintain full reversibility and outstanding dynamic exchange rates. Remarkably, the C?C bonds can be formed or cleaved by the addition or removal of lithium cations, permitting unprecedented control over the system's constitutional state. Moreover, the metal-ligand cooperative substrate interaction allows to twist the kinetics of catalytic hydroboration reactions in a unique sense. Ultimately, this work describes the evolution of an anti-van't Hoff/Le Bel species from their being as a structural curiosity to their application as a reagent and catalyst.
- Ebner, Fabian,Greb, Lutz,Sigmund, Lukas Maximilian
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supporting information
p. 17118 - 17124
(2020/08/21)
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- Construction of Silicon-Containing Seven-Membered Rings by Catalytic [4 + 2 + 1] Cycloaddition through Rhodium Silylenoid
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A rhodium-catalyzed [4 + 2 + 1] cycloaddition involving 1,3-diene, alkyne, and silylene to afford silicon-containing seven-membered rings was established. In the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM), nona-1,3-dien-8-yne derivatives reacted efficiently at 80-110 °C with boryl(isopropoxy)silane or boryl(diethyamino)silane, which reacts as the synthetic equivalent of silylene, to afford 1-silacyclohepta-2,5-dienes (2,5-dihydro-1H-silepines). Regiodivergent and chemo- and stereoselective functionalization of the seven-membered nonconjugated diene was achieved by hydroboration mediated by Cs2CO3 or an iridium catalyst.
- Sasaki, Ikuo,Ohmura, Toshimichi,Suginome, Michinori
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supporting information
p. 2961 - 2966
(2020/04/10)
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- Expanding the limits of catalysts with low-valent main-group elements for the hydroboration of aldehydes and ketones using [L?Sn(ii)][OTf] (L? = aminotroponate; OTf = triflate)
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A triflatostannylene [L?Sn(ii)][OTf] (2) is reported here as an efficient catalyst with low-valent main-group element for the hydroboration of aldehydes and ketones (L? = aminotroponate). Using 0.025-0.25 mol% of compound 2, hydroboration of various aldehydes and ketones is accomplished in 0.13-1.25 h at room temperature; the aliphatic aldehydes show an impressive TOF of around 30?000 h?1. DFT calculations are performed to explore the mechanistic aspects of this reaction suggesting that the reaction proceeds via a stepwise pathway with hydridostannylene [L?Sn(ii)H] (2a) as the active catalyst and the H atom transfer from the Sn-H bond to the carbonyl carbon being the rate determining step.
- Sharma, Mahendra Kumar,Ansari, Mursaleem,Mahawar, Pritam,Rajaraman, Gopalan,Nagendran, Selvarajan
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p. 664 - 672
(2019/01/08)
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- POCN Ni(ii) pincer complexes: Synthesis, characterization and evaluation of catalytic hydrosilylation and hydroboration activities
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A series of iminophosphinite POCN pincer Ni(ii) complexes, (POCN)NiMe and (POCN)NiLn(BX4) (L = CH3CN, n = 0, 1; X = F, Ph, C6F5), have been developed and subjected to catalytic hydrosilylation of alkenes, aldehydes and ketones and hydroboration of carbonyl compounds. The stoichiometric reactivity of (POCN)NiMe and (POCN)Ni(BF4) with PhSiH3 and HBPin suggests that catalytic reactions proceed via the hydride intermediate (POCN)NiH. With regard to reactions with HBPin, efficient and mild hydroboration of a variety of carbonyl compounds, including highly chemoselective hydroboration of benzaldehyde in the presence of other common potent reductive functional groups, such as alkenes, alkynes, esters, amides, nitriles, nitro compounds and even ketones, and the first example of base metal catalyzed hydroboration of amides, including mild direct hydroborative reduction of primary and secondary amides to borylated amines were demonstrated for (POCN)NiMe.
- Gudun, Kristina A.,Segizbayev, Medet,Adamov, Assyl,Balanay, Mannix P.,Khalimon, Andrey Y.,Plessow, Philipp N.,Lyssenko, Konstantin A.
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supporting information
p. 1732 - 1746
(2019/03/07)
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- Practical and selective hydroboration of aldehydes and ketones in air catalysed by an iron(ii) coordination polymer
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The in air catalytic hydroboration of ketones and aldehydes with pinacolborane by an iron(ii) coordination polymer (CP) is carried out under mild and solvent-free conditions. The precatalyst is highly active towards a wide range of substrates including functionalized ketones and aldehydes in the presence of KOtBu as an activator, achieving a high turnover number (TON) of up to 9500. Excellent chemoselectivity to aldehydes over ketones was also revealed, which is in sharp contrast with the results obtained under inert atmosphere using the same catalyst system. This catalyst observed here is not only highly efficient but also recyclable for reuse for at least 5 times without losing its effectiveness.
- Zhang, Guoqi,Cheng, Jessica,Davis, Kezia,Bonifacio, Mary Grace,Zajaczkowski, Cynthia
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p. 1114 - 1121
(2019/03/12)
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- Ge(ii) cation catalyzed hydroboration of aldehydes and ketones
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Well-defined germylene cations [(i-Bu)2ATI]GeOTf (4) and [(i-Bu)2ATIGe][GaCl4] (5) are isolated, and the catalytic utility of compound 4 for the hydroboration of a variety of aldehydes and ketones is reported (ATI = aminotroponiminate).
- Sinhababu, Soumen,Singh, Dharmendra,Sharma, Mahendra Kumar,Siwatch, Rahul Kumar,Mahawar, Pritam,Nagendran, Selvarajan
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supporting information
p. 4094 - 4100
(2019/04/01)
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- La[N(SiMe3)2]3-Catalyzed Ester Reductions with Pinacolborane: Scope and Mechanism of Ester Cleavage
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Tris[N,N-bis(trimethylsilyl)amido]lanthanum (LaNTMS) is an efficient, highly active, and selective homogeneous catalyst for ester reduction with pinacolborane (HBpin). Alkyl and aryl esters are cleaved to the corresponding alkoxy- and aryloxy-boronic esters which can then be straightforwardly hydrolyzed to alcohols. Ester reduction is achieved with 1 mol % catalyst loading at 25-60 °C, and most substrates are quantitatively reduced in 1 h. Nitro, halide, and amino functional groups are well tolerated, and ester reduction is completely chemoselective over potentially competing intra- or intermolecular alkene or alkyne hydroboration. Kinetic studies, isotopic labeling, and density functional theory calculations with energetic span analysis argue that ester reduction proceeds through a rate-determining hydride-transfer step that is ligand-centered (hydride is transferred directly from bound HBpin to bound ester) and not through a metal hydride-based intermediate that is often observed in organolanthanide catalysis. The active catalyst is proposed to be a La-hemiacetal, [(Me3Si)2N]2La-OCHR(OR)[HBpin], generated in situ from LaNTMS via hydroboronolysis of a single La-N(SiMe3)2 bond. These results add to the growing compendium of selective oxygenate transformations that LaNTMS is competent to catalyze, further underscoring the value and versatility of homoleptic lanthanide complexes in homogeneous catalytic organic synthesis.
- Barger, Christopher J.,Motta, Alessandro,Weidner, Victoria L.,Lohr, Tracy L.,Marks, Tobin J.
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p. 9015 - 9024
(2019/10/02)
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- Asymmetric diimine monovalent magnesium compound, and preparation method and application thereof in epoxy silane hydroboration
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The invention discloses an asymmetric diimine monovalent magnesium compound, and a preparation method and application thereof in epoxy silane hydroboration. Reaction of borate synthesized from alkylene oxide and pinacolborane is catalyzed with the monovalent magnesium compound for the first time, the catalytic activity is relatively high, the structure is simple, the synthesis is easy, a new solution is provided for preparation of borate through hydroboration of an epoxide compound and borane, and the application of the monovalent magnesium compound is extended. The monovalent magnesium compound can catalyze hydroboration of epoxide and borane with high-activity, the catalyst use amount of aromatic epoxide or fatty epoxide is only 5% of the molar weight of a substrate, the reaction selectivity is high, the reaction product is mainly a Markovnikov addition product, almost 100% of conversion rate can be reached, the reaction selectivity is high, the reaction is simple and controllable, and the green chemical concept is highly met.
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Paragraph 0069; 0070
(2018/10/19)
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- Supported Single-Site Ti(IV) on a Metal-Organic Framework for the Hydroboration of Carbonyl Compounds
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A stable and structurally well-defined titanium alkoxide catalyst supported on a metal-organic-framework (MOF) of UiO-67 topology (ANL1-Ti(OiPr)2) was synthesized and fully characterized by a variety of analytical and spectroscopic techniques, including BET, TGA, PXRD, XAS, DRIFT, SEM, and DFT computations. The Ti-functionalized MOF was demonstrated active for the catalytic hydroboration of a wide range of aldehydes and ketones with HBpin as the boron source. Compared to traditional homogeneous and supported hydroboration catalysts, ANL1-Ti(OiPr)2 is completely recyclable and reusable, making it a promising hydroboration catalyst alternative for green and sustainable chemical synthesis. In addition, ANL1-Ti(OiPr)2 catalyst exhibits remarkable hydroboration selectivity toward aldehydes vs ketone in competitive study. DFT calculations suggest that the catalytic hydroboration proceeds via a (1) hydride transfer between the active Ti-hydride species and a carbonyl moiety (rate-determining step) and (2) alkoxide transfer (intramolecular σ-bond metathesis) to generate the borate ester product.
- Huang, Zhiyuan,Liu, Dong,Camacho-Bunquin, Jeffrey,Zhang, Guanghui,Yang, Dali,López-Encarnación, Juan M.,Xu, Yunjie,Ferrandon, Magali S.,Niklas, Jens,Poluektov, Oleg G.,Jellinek, Julius,Lei, Aiwen,Bunel, Emilio E.,Delferro, Massimiliano
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p. 3921 - 3930
(2017/10/30)
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- Nucleophile-selective cross-coupling reactions with vinyl and alkynyl bromides on a dinucleophilic aromatic substrate
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A nucleophile-selective cross-coupling reaction on an aromatic compound bearing two metal groups, Bpin and SnMe3, has been developed. Previously, only aryl bromides and iodides could be used as electrophilic components, but in this work, the scope could be extended to vinyl and alkynyl bromides as electrophiles. This means that the roles typical in Sonogashira couplings or Heck reactions of the aromatic ring as the dielectrophile coupling to vinyl and alkynyl metal species are reversed, which presents a new tool for organic synthesis. The first nucleophilic site to react is the stannyl group, and subsequently, a Suzuki-Miyaura cross-coupling reaction can take place on the same molecule.
- He, Lu-Ying,Schulz-Senft, Mathias,Thiedemann, Birk,Linshoeft, Julian,Gates, Paul J.,Staubitz, Anne
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supporting information
p. 2498 - 2502
(2015/04/22)
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- 7-(lH-PYRAZOL-4-YL)-1,6-NAPHTHYRIDINE COMPOUNDS AS SYK INHIBITORS
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The present invention relates to a compound of formula (I): or a salt thereof; which is an inhibitor of spleen tyrosine kinase (Syk) and therefore potentially of use in treating diseases resulting from inappropriate activation of mast and/or basophil cells, macrophages, and B-cells and related inflammatory responses and tissue damage, for instance inflammatory disease and/or allergic disorders, and in cancer therapy, specifically heme malignancies, chronic spontaneous urticaria and autoimmune conditions.
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Paragraph 0482-0483
(2013/03/26)
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- Dual selectivity: Electrophile and nucleophile selective cross-coupling reactions on a single aromatic substrate
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The development of a high yielding, both nucleophile and electrophile selective cross-coupling reaction with aromatic rings is presented. The reaction is general with respect to functional groups. Furthermore, the products still contain a boronic ester and a bromide. These two functional groups allow them to be easy-to-prepare, highly complex starting materials for further reactions, avoiding protecting group transformations.
- Heinrich, Annika C. J.,Thiedemann, Birk,Gates, Paul J.,Staubitz, Anne
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supporting information
p. 4666 - 4669
(2013/10/08)
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- A modular synthesis of teraryl-based α-helix mimetics, part 2: Synthesis of 5-pyridine boronic acid pinacol ester building blocks with amino acid side chains in 3-position
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One of the most common protein-protein interactions (PPI) is the interaction of the α-helix of one protein with the surface of the second one. Terphenylic scaffolds are bioinspired motifs in the inhibition of PPIs and have been identified as suitable α-helix mimetics. One of the challenging aspects of this strategy is the poor solubility of terphenyls under physiological conditions. In the literature pyrrolopyrimidine-, pyrimidine- or pyridazine-based mimetics have been reported to show improved solubility. We present a new convergent strategy for the synthesis of linear pyridine-type teraryls based on a phenylic core unit. A general approach for the synthesis of 3,5-disubstituted pyridine-based boronic acid pinacol esters with amino acid side chains in the 3-position (representing Phe, Leu, Ile, Lys, Asp, Asn) is presented and exploits the functional group tolerance of the Knochel-Grignard reagents. The building blocks have been used in a convergent in situ two-step synthesis of teraryl α-helix mimetics. Tune in: The chemical orthogonality of Knochel's Grignard chemistry enables the synthesis of 3-substituted 5-pyridine-boronic esters with amino acid side chains, which can be used for convenient assembly of teraryl-based α-helix peptide mimetics by Suzuki coupling (see scheme; dppf=1,1′-bis(diphenylphosphino)ferrocene, DME= dimethoxyethane, Tf=trifluoromethanesulfonyl). Copyright
- Peters, Martin,Trobe, Melanie,Breinbauer, Rolf
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supporting information
p. 2450 - 2456
(2013/03/28)
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- Preparative synthesis via continuous flow of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane: A general propargylation reagent
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A scalable process for the preparation of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane from trimethylsilylpropyne, isopropyl pinacol borate, and n-butyllithium is described. Problems associated with implementing a typical aqueous workup and batch process into production due to borolane ate equilibration and protonolysis are presented. To address these issues, a continuous-flow and distillation process was developed which efficiently produced 297 kg of the key propargylation reagent.
- Fandrick, Daniel R.,Roschangar, Frank,Kim, Chunyoung,Hahm, Byoung J.,Cha, Myoung H.,Kim, Hyoun Y.,Yoo, Gyesang,Kim, Taeyun,Reeves, Jonathan T.,Song, Jinhua J.,Tan, Zhulin,Qu, Bo,Haddad, Nizar,Shen, Sherry,Grinberg, Nelu,Lee, Heewon,Yee, Nathan,Senanayake, Chris H.
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supporting information; scheme or table
p. 1131 - 1140
(2012/08/13)
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- Chemoselective cross-coupling reactions with differentiation between two nucleophilic sites on a single aromatic substrate
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A new thiophene building block, containing both a stannyl group and a boronic ester, was prepared. From this starting material, a general, nucleophile-selective one-pot reaction was developed, exploiting the different reactivities of the Stille and Suzuki-Miyaura cross-coupling reactions. A series of aromatic electrophiles were used to demonstrate the high functional group tolerance.
- Linshoeft, Julian,Heinrich, Annika C. J.,Segler, Stephan A. W.,Gates, Paul J.,Staubitz, Anne
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supporting information
p. 5644 - 5647
(2013/01/15)
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- 7-(1H-PYRAZOL-4-YL)-1,6-NAPHTHYRIDINE COMPOUNDS AS SYK INHIBITORS
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A compound of formula (I) or a salt thereof; which is an inhibitor of spleen tyrosine kinase (Syk) and therefore potentially of use in treating diseases resulting from inappropriate activation of mast and/or basophil cells, macrophages, and B-cells and related inflammatory responses and tissue damage, for instance inflammatory disease and/or allergic disorders, and in cancer therapy, specifically heme malignancies, chronic spontaneous urticaria and autoimmune conditions.
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Page/Page column 16; 17; 72; 73
(2011/11/13)
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- PROCESSES FOR PREPARING JAK INHIBITORS AND RELATED INTERMEDIATE COMPOUNDS
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The present invention is related to processes for preparing chiral substituted pyrazolyl pyrrolo[2,3-d]pyrimidines of Formula III, and related synthetic intermediate compounds. The chiral substituted pyrazolyl pyrrolo[2,3-d]pyrimidines are useful as inhibitors of the Janus Kinase family of protein tyrosine kinases (JAKs) for treatment of inflammatory diseases, myeloproliferative disorders, and other diseases.
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Page/Page column 104
(2010/08/07)
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- Convenient access to various 1-cyclopropylcyclopropane derivatives
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1-Bromo-1-cyclopropylcyclopropane (1), which is easily accessible in two steps from methyl cyclopropanecarboxylate, does not form a stable Grignard reagent: upon reaction with elemental magnesium, yet it readily undergoes bromine/ lithium exchange without rearrangement upon treatment with tert-butyllithium in diethyl ether/pentane at -78 °C, and the resulting 1-lithio-1-cyclopropylcyclopropane can be trapped with various electrophiles to give the correspondingly 1-substituted bicyclopropyl derivatives 10 in yields ranging from 38 to over 90 % (13 examples). The (1-cyclopropylcyclopropyl) boronate 10m, which is also obtained from the 1-lithio derivative, has been subjected to Suzuki cross couplings with a number of aryl halides to furnish 1-aryl-1,1′bicyclopropyl compounds 11 (4 examples, 14-50% yield), predominantly without rearrangement. Further transformations of 1-cyclopropylcyclopropanecarbaldehyde (10e) have provided 2-(1- cyclopropylcyclopropyl)glycme (16), ethyl 3-(1-cyclopropylcyclopropyl)acrylate (17), and its cycloadducts with the nitrone 18 and cyclopentadiene 19, albeit the latter only in poor yield.
- De Meijere, Armin,Khlebnikov, Alexander F.,Suennemann, Hans Wolf,Frank, Daniel,Rauch, Karsten,Yufit, Dmitrii S.
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experimental part
p. 3295 - 3301
(2010/08/22)
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- Enantioselective synthesis of janus kinase inhibitor INCB018424 via an organocatalytic aza-michael reaction
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An enantioselective synthesis of INCB018424 via organocatalytic asymmetric aza-Michael addition of pyrazoles (16 or 20) to (E)-3- cyclopentylacrylaldehyde (23) using diarylprolinol silyl ether as the catalyst was developed. Michael adducts (R)-24 and (R)-27 were isolated in good yield and high ee and were readily converted to INCB018424.
- Lin, Qiyan,Meloni, David,Pan, Yongchun,Xia, Michael,Rodgers, James,Shepard, Stacey,Li, Mei,Galya, Laurine,Metcalf, Brian,Yue, Tai-N,Liu, Pingli,Zhou, Jiacheng
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supporting information; experimental part
p. 1999 - 2002
(2009/09/06)
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- Stereoselective Synthesis of Alcohols, XXX. - E- and Z-Pentenylboronates, Reagents for Simple Diastereoselection on Addition to Aldehydes
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Pentenylboronates, either >90percent Z (4) or >95percent E (3), can be obtained by reaction of the pentenyl Grignard reagent with different borates.The Z-pentenylboronates 4 add to aldehydes under high simple diastereoselection to give the diastereomerically pure syn-homoallyl alcohols 10.The corresponding addition of the E-pentenylboronates leads to the anti-homoallyl alcohols as E-(15)/Z-(17) mixtures. - Key Words: Homoallyl alcohols/ Diastereoselectivity/ Allylboranes
- Andersen, Marc W.,Hildebrandt, Bernhard,Koester, Gerhard,Hoffmann, Reinhard W.
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p. 1777 - 1782
(2007/10/02)
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