- Lithium Hexaphenylrhodate(III) and-Iridate(III): Structure in the Solid State and in Solution
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Anionic homoleptic organo-Transition metal complexes can be prepared from organolithium reagents and transition metal salts and are key reactive intermediates in C-C bond formation. However, the interaction between the anionic component and cationic counterparts of multianionic homoleptic organo-Transition metal complexes in solution remains unclear, unlike well-studied monoanionic complexes such as organocuprates. Here we have prepared and structurally characterized lithium hexaphenylrhodate(III) and-iridate(III) complexes, [Li(12-crown-4)2][MPh6{Li(thf)}2] (M = Rh and Ir), as the first examples of hexaaryl complexes of d6 metals. In the crystals, two Li cations contact the trianionic MPh6 moiety, while the other exists as a solvent-separated ion pair. In THF, hexaphenylrhodate decomposed within 1 h. In contrast, the Ir analog was stable. 7Li NMR and X-ray absorption fine structure analysis revealed the solution-phase structure of hexaphenyliridate, which maintained a partially contacted ion pair structure even in THF, a coordinating solvent.
- Iwasaki, Takanori,Hirooka, Yuko,Takaya, Hikaru,Honma, Tetsuo,Nozaki, Kyoko
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Read Online
- CETONES PYRIDINIQUES. VIII. METALLATION REGIOSELECTIVE DE LA s-COLLIDINE: EFFETS DE METAUX ET DE SOLVANTS
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The regioselective metalation of s-collidine yielding two anions, trapped by PhCN, was found to be essentially determined by the solvent and the size of the cation: twelve solvents and three cations (Li+, Na+, K+) were examined.The effect of various bases (alkali metals, phenyllithium, amides, "complex bases", amines) and of some metallic cations (Li+, Ag+, Pd2+) was studied.The solvent basicity was not responsible for the regioselectivity.
- Compagnon, P.-L.,Kimny, Tan
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Read Online
- The Anionic Pathway in the Nickel-Catalysed Cross-Coupling of Aryl Ethers
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The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C?C and C?heteroatom bonds. However, the inert C(sp2)?O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.
- Borys, Andryj M.,Hevia, Eva
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supporting information
p. 24659 - 24667
(2021/10/20)
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- Phenylchromium(III) Chemistry Revisited 100 Years after Franz Hein (Part II): From LinCrPh3+ n(thf)x(n = 1, 2, 3) to Dimeric Triphenylchromate(II) Complexes
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Polyphenylchromium(III) organometallics with various phenylation degrees and stabilized by diverse Lewis bases with various donor strengths and denticity were investigated in order to better understand the formation of (η6-arene)chromium complexes according to the procedure of Franz Hein (1892-1976) [ Organometallics 2019, 38, 498-511, DOI: 10.1021/acs.organomet.8b00811]. Part II focuses on hexa-, penta-, and tetraphenylchromates(III). Chromium(III) compounds with a lower phenylation degree will be discussed in a future part III. The numbering scheme of the complexes relates to the number of Cr-bound phenyl substituents. Hexaphenylchromate(III): The reaction of Ph3Cr(thf)3·0.25dx (3) (dx = 1,4-dioxane) with an ethereal solution of phenyllithium yields yellow-orange [Li3CrPh6(thf)2.3(OEt2)0.7] (6-thf-OEt2) which slowly degrades in contact with the reaction solution leading to emerald-green crystals of [{(Et2O)Li}2Ph3Cr(μ-O)]2 (3-Li2O). Pentaphenylchromate(III): Compound 6-thf-OEt2 reacts with 1 equiv of HCl-OEt2 solution to turquoise [{(thf)2Li}{(Et2O)Li}CrPh5] (5-thf-OEt2) that reacts with THF to the green contact ion pair [{(thf)2Li}2CrPh5] (5-thf) and with 12-crown-4 (12C4) to the light green solvent-separated ion pair [(12C4)Li(thf)]2 [CrPh5] (5-thf-12C4). Refluxing of 5-thf-OEt2 in diethyl ether leads to ether degradation and formation of 3-Li2O, whereas 5-thf-12C4 liberates biphenyl under similar reaction conditions. Tetraphenylchromate(III): The reaction of 3 with 1 equiv of phenyllithium in THF leads to a green reaction mixture. At -50 °C, red [(thf)4Li] [cis-(thf)2CrPh4]·2THF (4-thf) crystallizes which reversibly transforms into a green oil above -50 °C. Upon acidolysis of 5-thf-OEt2 with 1 equiv of HCl-OEt2 at -20 °C, the intermediately formed red complex is reduced to the dinuclear chromate(II) [{(thf)Li}CrPh3]2 (3-CrII-thf) (Cr-Cr 187.66(8) pm). Recrystallization of this product from THF yields solvent-separated [(thf)4Li]2 [(CrPh3)2] (3-CrII-thf4) with a Cr-Cr quadruple bond (Cr-Cr 183.7(2) pm) without contacts between the lithium ions and Cr-bound phenyl groups. Complex 3-CrII-thf reacts at room temperature in diethyl ether to the sandwich complexes bis(biphenyl)chromium(0) [(η6-Ph2)2Cr0] (π-4) and benzene-biphenylchromium(0) [(η6-C6H6)(η6-Ph2)Cr0] (π-3). Compounds in bold letters are authenticated by X-ray structure determinations.
- Fischer, Reinald,G?rls, Helmar,Suxdorf, Regina,Westerhausen, Matthias
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p. 3892 - 3905
(2020/11/13)
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- Systematic synthesis and crystal structures of tetraaryltellurium compounds Ar4TeIV
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Hypervalent tetraaryltellurium(IV) compounds of the type Ar4TeIV(1: Ar = C6H5; 2: Ar = p-H3CC6H4; 3: Ar = p-t-BuC6H4; 4: Ar = p-F3CC6H4) were prepared via a convenient one-pot reaction between the isolated corresponding ArLi reagent and TeCl4. X-ray crystallographic analyses of 14 revealed distorted pseudo-trigonal-bipyramidal (TBP) structures for Ar4Te and the TBP character was analyzed by the dihedral angle method.
- Kobayashi, Sho,Sugamata, Koh,Minoura, Mao
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supporting information
p. 661 - 663
(2019/04/05)
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- Generation of Phosphonium Sites on Sulfated Zirconium Oxide: Relationship to Br?nsted Acid Strength of Surface -OH Sites
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The reaction of (tBu)2ArP (1a-h), where the para position of the Ar group contains electron-donating or electron-withdrawing groups, with sulfated zirconium oxide partially dehydroxylated at 300 °C (SZO300) forms [(tBu)2ArPH][SZO300] (2a-h). The equilibrium binding constants of 1a-h to SZO300 are related to the pKa of [(tBu)2ArPH]; R3P that form less acidic phosphoniums (high pKa values) bind stronger to SZO300 than R3P that form more acidic phosphoniums (low pKa values). These studies show that Br?nsted acid sites on the surface of SZO300 are not superacidic.
- Rodriguez, Jessica,Culver, Damien B.,Conley, Matthew P.
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supporting information
p. 1484 - 1488
(2019/01/25)
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- Dichotomy within 1,4-addition of organolithium and Grignard reagents to α,β-unsaturated Fischer alkoxycarbenes: A new synthesis of Fischer carbenes
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The reaction of organolithium and Grignard reagents with pentacarbonyl[(ethoxy)(2-phenylethenyl)carbene]chromium(0) gave, after the quenching of the initially formed product of the 1,4-addition, different products depending on the organometallic and quenching reagents used. The addition of organolithiums, followed by a work-up with acid (AcOH or HCl), afforded the corresponding carbene complexes. In contrast, quenching the reaction mixture with ethanol led to the stereoselective formation of (Z)-enol ethers. The usage of Grignard reagents led to the formation of the carbene complexes regardless of which quenching reagent was used.
- Tobrman, Tomá?,Polák, Peter,?ubiňák, Marek,Dvo?áková, Hana,Dvo?ák, Dalimil
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p. 2175 - 2181
(2019/03/05)
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- Synthetic, structural and reaction chemistry of N-heterocyclic germylene and stannylene compounds featuring: N -boryl substituents
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This study details the syntheses of N-heterocyclic germylenes and stannylenes featuring diazaborolyl groups, {(HCDippN)2B} (Dipp = 2,6-iPr2C6H3), as both of the N-bound substituents, with a view to generating electron rich and sterically protected metal centres. The energies of their key frontier orbitals-the group 14-centred lone pair and orthogonal pπ-orbital (typically the HOMO-2 and LUMO) have been probed by DFT calculations and compared with a related acyclic analogue, revealing (in the case of the stannylenes) a correlation with the measured 119Sn chemical shifts. The reactivity of the germylene systems towards oxygen atom transfer agents has been examined, with 2:1 reaction stoichiometries being observed for both Me3NO and pyridine N-oxide, leading to the formation of products thought to be derived from the activation of C-H bonds by a transient first-formed germanone.
- Kristinsdóttir, Lilja,Oldroyd, Nicola L.,Grabiner, Rachel,Knights, Alastair W.,Heilmann, Andreas,Protchenko, Andrey V.,Niu, Haoyu,Kolychev, Eugene L.,Campos, Jesús,Hicks, Jamie,Christensen, Kirsten E.,Aldridge, Simon
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supporting information
p. 11951 - 11960
(2019/08/14)
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- Preparation method of phenyl lithium
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The invention discloses a preparation method of phenyl lithium. The method comprises the following steps of (1) under the protection of inert gas, feeding natrium-lithium alloy and n-butyl ether intoa system; performing stirring to obtain a natrium-lithium alloy dispersion solution; (2) under the condition of 10 to 30 DEG C, dripping bromobenzene into the obtained natrium-lithium alloy dispersionsolution obtained in the step (1) under the stirring condition; controlling the system temperature to be 10 to 30 DEG C; after the dripping is completed, performing heat insulation reaction; performing treatment to obtain a phenyl lithium solution. The n-butyl ether is used for replacing the conventional diethyl ether or diethyl ether-phenyl mixed solution; the reaction temperature is strictly controlled, so that the reaction is successfully triggered; the product purity is high; the industrial scaled production of the phenyl lithium is realized.
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Paragraph 0031-0034; 0037; 0038; 0040; 0041; 0043; 0044
(2018/04/03)
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- A Zinc Catalyzed C(sp3)?C(sp2) Suzuki–Miyaura Cross-Coupling Reaction Mediated by Aryl-Zincates
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The Suzuki–Miyaura (SM) reaction is one of the most important methods for C?C bond formation in chemical synthesis. In this communication, we show for the first time that the low toxicity, inexpensive element zinc is able to catalyze SM reactions. The cross-coupling of benzyl bromides with aryl borates is catalyzed by ZnBr2, in a process that is free from added ligand, and is compatible with a range of functionalized benzyl bromides and arylboronic acid pinacol esters. Initial mechanistic investigations indicate that the selective in situ formation of triaryl zincates is crucial to promote selective cross-coupling reactivity, which is facilitated by employing an arylborate of optimal nucleophilicity.
- Procter, Richard J.,Dunsford, Jay J.,Rushworth, Philip J.,Hulcoop, David G.,Layfield, Richard A.,Ingleson, Michael J.
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supporting information
p. 15889 - 15893
(2017/10/24)
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- PROCESS FOR THE PREPARATION OF 4-PHENYLDIBENZOTHIOPHENE
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The invention relates to a novel method for the preparation of 4-phenyldibenzo[b,d]thiophene which can be conducted in one pot up to the thiophene ring formation. The synthesis is based upon dihalobenzenes and phenyllithium, which are readily obtainable, and can give higher yields (based upon either reactant) than the yields current methods, which use a synthetic pathway based upon dibenzo[b,d]thiophene.
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Paragraph 0033
(2016/10/31)
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- Copper-catalysed cross-coupling of arylzirconium reagents with aryl and heteroaryl iodides
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An unprecedented CuI-catalysed cross-coupling of arylzirconium reagents with aryl and heteroaryl iodides is reported. Mechanistic studies with a Cp2ZrAr2 complex revealed that Cp2Zr(Ar)(Cl) is the reactive species that undergoes transmetalation with (PN-1)CuI. In addition, experiments with radical probes indicated that the reaction proceeds via a non-radical pathway. This journal is
- Thapa, Surendra,Basnet, Prakash,Gurung, Santosh K.,Giri, Ramesh
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supporting information
p. 4009 - 4012
(2015/03/30)
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- Fibre optic ATR-IR spectroscopy at cryogenic temperatures: In-line reaction monitoring on organolithium compounds
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A reliable methodology, utilising an ATR-IR fibre probe, for in-line monitoring of low temperature reactions is presented. The application of this convenient set-up enables a fast and safe exploration of highly reactive substrates. Hence, in situ monitoring of lithiation reactions is realised and the potential to investigate sensitive intermediates is being demonstrated. The Royal Society of Chemistry 2012.
- Lumpi, Daniel,Wagner, Christoph,Schoepf, Matthias,Horkel, Ernst,Ramer, Georg,Lendl, Bernhard,Froehlich, Johannes
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supporting information; body text
p. 2451 - 2453
(2012/04/10)
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- Synthesis of tetramethylammonium phenyltrialkylborate salts by the addition of alkyllithium reagents to a triorganylborane or organoboranylhalides
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Several new tetraorganylborate salts have been synthesized by the addition of alkyl or phenyllithium reagents to a triorganylborane or organoboranylhalides. The chemical structure of the borates was confirmed by 1H, 13C NMR and IR spectroscopic measurements and elemental analysis. Solubility, spectroscopic and electrochemical properties of these salts have been investigated as well. The structures of the phenyltrialkylborates were varied systematically to control their oxidation potential. These compounds are the trimethyl-, triethyl-, n-tributyl- and sec-tributylborate derivatives and form a series of substituted phenyltrialkylborates containing either electron-withdrawing or electron-donating substituents in the para position of phenyl ring. The oxidation potential of these borates has been found to be a function of Hammett constant.
- Pietrzak, Marek,Jdrzejewska, Beata
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body text
p. 2135 - 2141
(2011/06/20)
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- Evaluation of electron-deficient phosphine ligands for direct arylation of heterocycles
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New electron-deficient biarylphosphine ligands were studied and proved to be efficient for the direct arylation of heteroarenes with aryl iodides. The ability of a more electron-deficient palladium centre to accelerate the arylation of heterocycles that remained unreactive with aryl iodides in the past has been validated and these heteroarenes can now be smoothly reacted in the presence of a new electrophilic catalyst. Experimental evidence suggests a viable concerted metalation-deprotonation pathway for the C-H bond cleavage step with an electron-deficient palladium centre.
- Rene, Olivier,Fagnou, Keith
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supporting information; experimental part
p. 2116 - 2120
(2010/11/04)
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- STEREOSELECTIVE SYNTHESIS OF 17-α -AND 17-β -ARYL STEROIDAL COMPOUNDS
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A process for forming one or the other of a 17-α-aryl or 17-β-aryl steroidal compound in diastereo excess is disclosed. The process utilizes a 17-keto steroid to form a Δ16-17-aryl-steroid compound or a 17-β-hydroxy-17-α-aryl steroid compound that are reduced or deoxygenated, respectively, in the presence of Raney nickel to form a 17-β-aryl- steroid or 17-α-aryl steroid, respectively, in a diastereo ratio of at least 3:1.
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Page/Page column 33-34
(2010/01/29)
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- A facile method for promoting activities of ordered mesoporous silica-anchored Rh-P complex catalysts in 1-octene hydroformylation
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This work deals with the promotion of immobilized Rh catalyst activities in olefin hydroformylation by lengthening the alkyl spacers and choosing an active Rh precursor. The flexibility of long chain alkyls was used to free the motion of the anchored Rh c
- Zhou, Wei,He, Dehua
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experimental part
p. 1146 - 1154
(2010/05/18)
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- 2-Oxazoline/benzoxazole-1,10-phenanthrolinylmetal (iron, cobalt or nickel) dichloride: Synthesis, characterization and their catalytic reactivity for the ethylene oligomerization
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Series of 2-benzoxazole-1,10-phenanthrolines (L1-L4) and 2-oxazoline-1,10-phenanthrolines (L5-L8) were synthesized and used as tridentate N^N^N ligands in coordinating with metal (nickel, cobalt or iron) chlorides. Their metal complexes, nickel(II) (Ni1-Ni8), cobalt(II) (Co1-Co8) and iron(II) (Fe1-Fe8), were characterized by elemental and IR spectroscopic analyses. The molecular structures of the ligand L2 and the complexes Ni3, Co1, Co3 and Fe2 have been determined by the single-crystal crystallography. The nickel complex Ni3 and iron complex Fe2 display an octahedral geometry, whereas cobalt complex Co1 is with a distorted bipyramidal geometry and Co3 as square pyramidal geometry. At 10 atm ethylene, all the complexes showed good activities in ethylene dimerization upon activation with appropriate aluminum cocatalysts; the nickel complexes gave the activity up to 3.11 × 106 g mol-1(Ni) h-1 upon activation with diethylaluminum chloride (Et2AlCl), meanwhile the cobalt and iron complexes showed activities up to 1.51 × 106 g mol-1(Co) h-1 and 1.89 × 106 g mol-1(Fe) h-1, individually, upon activation with modified methylaluminoxane (MMAO).
- Zhang, Min,Gao, Rong,Hao, Xiang,Sun, Wen-Hua
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experimental part
p. 3867 - 3877
(2009/04/07)
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- T-CELL INHIBITING COMPOUNDS AND THEIR USE FOR THE TREATMENT OF T-CELL-MEDIATED DISEASES
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The present invention relates to compounds of formula IA or IB. The present invention also concerned to a method of treating immunologic diseases or pathological conditions in association with T cell involving an immunologic component using T-cell inhibitors, optionally in combination with one or more other drugs selected from steroids, DMARDs, NSAIDs, immunosuppressive, and biological modifiers, pharmaceutical compositions comprising said compounds of formula IA or IB together with said other drugs, and the use of T-cell inhibitors for the manufacture of a pharmaceutical composition for the treatment of immunologic diseases or pathological conditions involving an immunologic component.
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Page/Page column 24-25
(2008/12/07)
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- Aryl-and heteroaryl-substituted tetrahydrobenzazepines and use thereof to block reuptake of norepinephrine, dopamine, and serotonin
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The compounds of the present invention are represented by the following aryl- and heteroaryl-substituted tetrahydrobenzazepine and dihydrobenzazapine derivatives having formulae I(A-E) and formula (II): where the carbon atom designated * is in the R or S configuration, and the substituents X and R1-R9 are as defined herein.
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Page/Page column 132
(2008/06/13)
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- Derivatives of N-[phenyl(alkylpiperidine-2-yl)methyl]benzamide, preparation method thereof and application of same in therapeutics
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Compounds of formula (I) as defined herein: are useful for treating behavioral disorders associated with dementia, psychoses, in particular schizophrenia (deficient form and productive form) and acute or chronic extrapyramidal symptoms induced by neuroleptics; for the treatment of various forms of anxiety, panic attacks, phobias, and compulsive obsessive disorders; for treating various forms of depression, including psychotic depression; for treating disorders caused by alcohol abuse or weaning from alcohol, sexual behavior disorders, eating disorders and for treating migraine. Moreover, the compounds of the invention may be used for treating painful muscle contracture in rheumatology and in acute spinal pathology; for treating spastic contractures of medullary or cerebral origin; for the symptomatic treatment of acute and subacute pain of light to moderate intensity; for treating intense and/or chronic pain, neurogenic pain and intractable pain; for treating Parkinson's disease and Parkinson-like symptoms of neurodegenerative origin or induced by neuroleptics; for treating partial primary and secondary generalized epilepsy of simple or complex symptomology, mixed forms and other epileptic syndromes in addition to another antiepileptic treatment, or in monotherapy, for the treatment of sleep apnea, and for neuroprotection.
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Page/Page column 6-7
(2010/11/24)
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- METHOD FOR PRODUCING ALKYL LITHIUM COMPOUNDS AND ARYL LITHIUM COMPOUNDS BY MONITORING THE REACTION BY MEANS OF IR-SPECTROSCOPY
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The invention relates to a method for producing alkyl lithium compounds and aryl lithium compounds by reacting lithium metal with alkyl or aryl halogenides in a solvent, the concentration of the alkyl/aryl halogenide and the alkyl/aryl lithium compound being detected according to an in-line measurement in the reactor by means of IR spectroscopy, and an exact recognition of the end point of the dosing of the halogenide constituents being carried out by evaluation of the IR measurement. Said method enables an optimum reactive process and reaction yield. The identification of the respective concentration of the educt and the product is a reliable reactive process. The yield of the reaction is also optimised by determining the end point of the halogenide dosing, as is the purity of the product due to a lower concentration thereof during the reaction.
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Page/Page column 16
(2008/06/13)
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- CHEMICAL PROCESS
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Process for preparing compounds of Formula (I); and (IV); are described.
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Page/Page column 13
(2008/06/13)
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- Method for producing, via organometallic compounds, organic intermediate products
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The present invention provides a process for preparing aryllithium compounds by reacting haloaliphatics with lithium metal to form a lithium alkyl and reacting the lithium alkyl with aromatic halogen compounds of formula (III) in a halogen-metal exchange reaction to form the corresponding lithium aromatics of formula (IV).
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- METHOD FOR METAL-ORGANIC PRODUCTION OF ORGANIC INTERMEDIATE PRODUCTS BY MEANS OF ARYL LITHIUM-BASES
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The invention relates to a method for the production of substituted aromatic compounds by producing lithium arylene and by reacting it with suitable electrophiles. The method comprises the following steps (step 1); an aryl lithium compound ( auxiliary base'') is initially produced by reacting a halogen aromatic compound with lithium metal; said compound is subsequently (step 2) reacted for deprotonation of the aromatic substrate in order to form the corresponding lithium aromatic compound which is subsequently (step 3) reacted with a corresponding electrophile to form the desired substituted aromatic compound, see page 2 of the description.
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Page/Page column 15
(2010/02/06)
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- No-D NMR (No-Deuterium Proton NMR) spectroscopy: A simple yet powerful method for analyzing reaction and reagent solutions
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(Equation presented) The title technique is a convenient and powerful method for directly monitoring or assaying any reaction mixture or reagent solution. Examples of some common processes (Fischer esterification, lithiation, butyllithium/THF compatibility, olefin metathesis, and a quantification assay), each interrogated in its native solvent, are presented. The spectral data are easy to acquire, and the information content makes a compelling case for routine use of No-D NMR spectroscopy.
- Hoye, Thomas R.,Eklov, Brian M.,Ryba, Troy D.,Voloshin, Mikhail,Yao, Letitia J.
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p. 953 - 956
(2007/10/03)
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- Process for the preparation of pure aryllithium compounds and their use
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A process is described for preparing aryllithium compounds by reaction of metallic lithium in an ether-containing solvent with an aryl halide, wherein prior to or at the beginning of the reaction a catalyst is added, the catalyst containing a halogen-free, polynuclear aromatic (aryl catalyst) or consisting of such a compound.
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- The role of ate complexes in the lithium-sulfur, lithium-selenium and lithium-tellurium exchange reactions
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Hypervalent ate complexes are presumptive intermediates in the metal-halogen, metal-tellurium, and related exchange reactions. The effect of o,o′-biphenyldiyl vs. diphenyl substitution on formation of tellurium ate complexes was studied by a kinetic technique and by NMR spectroscopy. Only a modest increase in the association constant (Kate) was measured. When Li/M exchanges of o,o′-biphenyldiyl sulfides and selenides were made intramolecular by means of a m-terphenyl framework (12-S, 12-Se, 21), enormous increases (> 109) in the rate of Li/S and Li/Se exchange were observed compared to acyclic models. Apparently, these systems are ideally preorganized to favor the T-shaped geometry of the hypervalent intermediates. For the selenium systems, ate complex intermediates (20-Se, 26) were detected spectroscopically in THF- or THF/HMPA-containing solutions. A DNMR study showed that Li/Se exchange was substantially faster than exchange of the lithium reagents with the ate complex. Therefore, these ate complexes are not on the actual Li/Se exchange pathway.
- Reich, Hans J.,Gudmundsson, Birgir Oe.,Green, D. Patrick,Bevan, Martin J.,Reich, Ieva L.
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p. 3748 - 3772
(2007/10/03)
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- N-fluorotriazinium fluorinating agents
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Novel N-fluorotriazinium electrophilic fluorinating agents have the Formula I: wherein three A moieties are independently CR, where each R is, independently, hydrogen, halogen, hydroxyl, (primary, secondary or tertiary) amino, amino, cyano, perfluorothio, hydroxysulfonyl, halosulfonyl, hydrocarbyloxysulfonyl, or a carbon-containing substituent selected from the group consisting of optionally substituted hydrocarbyl, hydrocarbyloxy, hydrocarbyloxycarbonyl, and hydrocarbylthio groups, and at least one R is neither hydrogen nor halogen; two A moieties are independently Z, where each Z is independently nitrogen or a quaternary nitrogen atom and Y is a counterion or group of counterions which are inert to chemical attack by fluorine, or adjacent triazinium moieties are linked by a common R substituent to provide an oligomer or polymer. Preferably the compounds are 1,3,5-triazinium compound in which all R are the same, optionally perfluorinated, alkyl or alkoxy groups; Z1 and Z2 are both nitrogen and Y? is triflate. Compounds of Formula I are especially useful in fluorinating carbanionic species or activated aromatic compounds.
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- Synthesis of 5-Pyridyl-2-furaldehydes via palladium-catalyzed cross-coupling with triorganozincates
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(Equation Presented) 5-Pyridyl-and 5-aryl-2-furaldehydes are prepared from furaldehyde diethyl acetal in a four-step, one-pot procedure: (i) deprotonation; (2) Li to Zn transmetalation; (3) Pd-mediated cross-coupling; (4) aldehyde deprotection. Triorganozincate 7 was found to transfer all three groups in the Pd-catalyzed cross-coupling reaction with haloaromatics.
- Gauthier Jr., Donald R.,Szumigala Jr., Ronald H.,Dormer, Peter G.,Armstrong III, Joseph D.,Volante,Reider, Paul J.
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p. 375 - 378
(2007/10/03)
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- Arene-catalysed lithiation of fluoroarenes
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The reaction of different fluoroarenes 1 with lithium and a catalytic amount (7%) of naphthalene in THF at -30°C affords the corresponding aryllithium intermediates which, by reaction with several electrophiles at temperatures ranging between -30 and 0°C, lead to the expected products 2, after hydrolysis. (C) 2000 Elsevier Science Ltd.
- Guijarro, David,Yus, Miguel
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p. 1135 - 1138
(2007/10/03)
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- Enantioselective synthesis of 1,2-diamines via nucleophilic 1,2-addition to dibenzylamino-acetaldehyde-SAMP-hydrazone
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Nucleophilic 1,2-addition of RM/CeCl3 in THF or allyl Grignard reagent in toluene to dibenzylamino-acetaldehyde-SAMP-hydrazone 2 after reductive N-N bond cleavage leads to differently protected 1,2-diamines 4 in good yields and of high enantiomeric purity (ee = 92-99percent).The absolute configuration was determined by X-ray structure analysis on the 1,2-adduct 3e. - Keywords: SAMP-hydrazone; nucleophilic 1,2-addition; asymmetric synthesis; vicinal diamine; organocerium reagent
- Enders, Dieter,Chelain, Evelyne,Raabe, Gerhard
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p. 299 - 306
(2007/10/03)
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- Enantiospecific Synthesis of N-9-Phenylfluoren-9-yl-α-amino Ketones
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Enantiomerically pure N-(9-phenylfluoren-9-yl)-α-amino ketones were prepared in excellent yields by acylation of organolithium reagents with N-(9-phenylfluoren-9-yl)-α-amino acid-derived oxazolidinones. The method is not applicable for the acylation of Grignard reagents as they attack the methylenic carbon of the oxazolidinone to give the corresponding N-alkylated amino acids 13 in excellent yields. The resulting N-(9-phenylfluoren-9-yl)-α-amino ketones 8 could be stereoselectively reduced to the corresponding syn- or anti-β-amino alcohols depending upon the nature of the reducing agent.
- Paleo, M. Rita,Calaza, M. Isabel,Sardina, F. Javier
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p. 6862 - 6869
(2007/10/03)
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- Naphthalene-catalysed lithiation of functionalized chloroarenes: Regioselective preparation and reactivity of functionalized lithioarenes
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The lithiation of different functionalized chloroarenes (dichlorobenzenes 1 and 3, mono and dichlorophenols 9 and 14, and chloropivalanilides 18) in the presence of a catalytic amount of naphthalene leads to the corresponding functionalized lithioarenes, which react with electrophiles to give the expected polyfunctionalized aromatic molecules 2, 4, 10, 19, 21, 22 and 24 in a regioselective manner. In the case of starting from chlorinated phenols or anilides a deprotonation of the functional group is carried out prior to the lithiation process; only for 2-chloropivalanilide 18o a coupling reaction leading to 2-n-butylpivalanilide is observed when an excess of n-butyllithium is used in the deprotonation step.
- Guijarro, Albert,Ramon, Diego J.,Yus, Miguel
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p. 469 - 482
(2007/10/02)
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- Ceramide derivatives and their use as inhibitors of sphingolipid synthesis
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Ceramide derivatives of the following general formula STR1 are described, wherein the individual radicals have the following meanings: X=--NH or --CH2, R1 =H or C1-11 -alkyl, R2 =C2-9 -alkenyl, wherein the double bond is in α position to the OR3 group R3 =H, C1-6 -alkyl or C1-6 -acyl and R4 =OH, C1-6 -alkoxy or morpholino. These ceramide derivatives represent inhibitors of the biosynthesis of sphingolipids.
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- MECHANISM OF THE EXCHANGE OF RADICALS BETWEEN TRIPHENYLARSENIC AND PHENYLLITHIUM IN VARIOUS BENZENE-TETRAHYDROFURAN MIXTURES
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A kinetic study was carried out on radical exchange between triphenylarsenic and phenyllithium in various benzene-tetrahydrofuran mixtures.The kinetic and activation parameters were calculated for the exchange reaction.The exchange rate increases and the activation parameters are reduced with increasing mole fraction of tetrahydrofuran due to nonspecific solvation.The results are in accord with a dipole-dipole interaction.
- Severin, A. V.,Batalov, A. P.
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p. 1494 - 1498
(2007/10/02)
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- Process for the preparation of sphingosine derivatives
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The invention relates to a new process for the preparation of the sphingosine derivatives described in European Patent Application No. 146,810, of the formula: STR1 It comprises protecting D-galactose in the 4,6-position and oxidizing it to the corresponding D-threose protected in the 2,4-position, condensing an aliphatic chain (R3) onto the latter by a Wittig reaction, converting the free hydroxyl group into a azido group and splitting off the protective group, protecting the resulting 2-azido-1,3-dihydroxy compound selectively in the 1-position and blocking it in the 3-position, liberating the 1-hydroxy group again, glycosidating the resulting compound or the abovementioned 2-azido-1,3-dihydroxy compound with the 0-trifluoro- or 0-trichloro-acetimade or the 1-halogen derivative of a 2,3,4,6-0-tetraacyl-D-glucose, splitting off the acyl groups of these and the protective group in the 3-position, converting the azido group into an amino group and acylating the amino compound with a fatty acid R1 --OH. The process gives the compounds of the therapeutically more active D series in a high yield in relatively few stages without resolving diastereomers.
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- Formation and Reactions of 1-Lithiobicyclopentane
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Bicyclopentyllithium was prepared in two steps from the readily available propellane and proved to be a versatile intermediate in the preparation of a wide variety of 1-substituted bicyclopentanes.
- Wiberg, Kenneth B.,Waddell, Sherman T.
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p. 289 - 292
(2007/10/02)
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- Structural investigation of aryllithium clusters in solution I. A 13C and 7Li NMR study of phenyllithium and some methyl-substituted phenyllithium derivatives
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13C and 7 Li NMR spectra of phenyllithium and several methyl substituted phenyllithium derivatives have been recorded in the presence of known amounts of coordinating solvents such as monodentate diethyl ether and THF and the potentially bidentate TMEDA (tetramethylethylenediamine).The relative amounts of the tetrameric and dimeric aggregates identified in these spectra depend on the donor strength, on the amount and dencity of added donor, and the presence or absence of ortho substitutents in the phenyl group.Discrete solvated tetrameric aggregates were formed upon addition of exactly one equivalent of the monodentate donor solvent to an aryllithium compound having no ortho substituents; the addition of either two equivalents or excess of monodentate donor solvent or one equivalent of bidentate donor ligand afforded dimeric species.When one or two methyl substituents were present ortho to the lithium-carbon bond, either a mixture of dimeric and tetrameric species was formed (one methyl group) or the dimeric species was exclusively formed (two methyl groups).
- Wehman, Erik,Jastrzebski, Johann T. B. H.,Ernsting, Jan-Meine,Grove, David M.,Koten, Gerard van
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p. 133 - 144
(2007/10/02)
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- Competitive Dienone-Phenol Type Rearrangements for the Regioselective Preparation of 2,4-Disubstituted-Naphth-1-ols
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The regioselective preparation of 2,4-substituted-naphth-1-ols via a variant of the dienone-phenol rearrangement is described.
- Dodge, Jeffrey A.,Chamberlin, A. Richard
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p. 4827 - 4830
(2007/10/02)
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- ORGANOSULPHUR COMPOUNDS-LXIX OPTICALLY ACTIVE SULPHINATES: A NEW TYPE OF ENANTIOSELECTIVE ASYMMETRIC SYNTHESIS AND KINETIC RESOLUTION
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Optically active sulphinates with the sulphur atom as a sole centre of chirality are prepared by two methods.The first involves the reaction of symmetrical sulphites with tert-butylmagnesium chloride in the presence of optically active aminoalcohols.This new asymmetric, enantioselective synthesis affords t-butylsulphinates with 40-70percent enantiomeric excess values.The second approach is based on a new type of kinetic resolution taking place when racemic sulphinates are reacted with tert-butylmagnesium chloride complexed by optically active alkaloid bases.Both the recovered sulphinates and sulphoxides formed in this reaction show moderate optical purities.
- Drabowicz, Jozef,Legedz, Slawomir,Mikolajczik, Marian
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p. 5243 - 5252
(2007/10/02)
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- REACTION OF ETHOXYCARBONYLCARBENE WITH 2-(3-METHYL-2-BUTENYLIDENE)ADAMANTANE
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The cyclopropanation products are formed in the reaction of ethoxycarbonylcarbene, produced by the thermocatalytic decomposition of ethyl diazoacetate, with methyleneadamantane and 2-(3-methyl-2-butenylidene)adamantane.In reaction with the diene the carbene adds the double bond furthest from the adamantane ring.
- Kostikov, R. R.,Boganov, S. E.,Molchanov, A. P.,Slobodin, Ya. M.
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p. 1084 - 1087
(2007/10/02)
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- THE CLEAVAGE OF P-C BONDS IN DIPHOSPHINES BY LITHIUM: THE CRYSTAL STRUCTURE OF 2(OC4H8)8>
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Reaction of alkane-1,n-diylbisdiphenylphosphines with lithium in tetrahydrofuran gives only the diphosphides resulting from cleavage of a phosphorus-aryl bond at each end of the chain; the course of the reaction is independent of chain length.The X-ray structure of the ethane diphosphide is presented and a possible mechanism discussed.
- Brooks, Peter,Craig, Donald C.,Gallagher, Michael J.,Rae, A. David,Sarrof, Adrien
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- REAKTIONSWAERMEN ISOMERER (LITHIOARYL)ETHER MIT s-BUOH
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The enthalpies of (2-lithioaryl) ethers and that of 8-lithio-1-methoxynaphthyllithium in di-n-butyl ether are lower than those of their 4-lithio isomers by ca. 20 and 28 kJ/(mol RLi), respectively.
- Klumpp, G. W.,Sinnige, M. J.
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p. 2247 - 2250
(2007/10/02)
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- Exocyclic P-C vs. Endocyclic P-P Bond Cleavage in 1,2-Diphosphetes. A Competition between Cyclic Delocalization and Cyclic Strain Controlled by the Substitution Pattern
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Attack by lithium on 1,2-diphenyl-3,4-di-R-substituted-1,2-diphosphetes takes place on the endocyclic P-P bond when R=Ph whereas it takes place on the exocyclic P-Ph bond when R=tBu; in this latter case, a 1,2-diphosphet-1-yl anion is obtained which is probably stabilized by cyclic delocalization.
- Charrier, Claude,Mathey, Francois,Robert, Francis,Jeannin, Yves
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p. 1707 - 1708
(2007/10/02)
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- 229. Bestimmung des Aggregationsgrads lithiumorganischer Verbindungen durch Kryoskopie in Tetrahydrofuran
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The association behaviour of alkyl-, aryl- and alkinyl-lithium compounds as well as of lithium enolates and chiral lithium azaenolates is determined from-freezing point depression values in dilute tetrahydrofuran solutions at -108 grad C.Compared to X-ray-crystallographic data (lithiated methyldithiane, phenyllithium, lithio derivatives of a ketone, carboxylic amide and -ester, and a diketopiperazine-bislactim-ether), desaggregation is found under these conditions.The structutres determined by 13C-NMR spectroscopy for BuLi, lithiophenylacetylene and (t-butyl)lithioacetylene are confirmed.The dilithio salt of a carboxylic acid is polymeric, a chiral lithio-hydrazone and a chiral lithio-oxazolidine are monomeric and dimeric, respectively.Lithium diisopropylamide is a monomer-dimer equilibrium mixture.The apparatus described permits both synthesis and measurement of the reactive species under inert atmosphere conditions in the same vessel.
- Bauer, Walter,Seebach, Dieter
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p. 1972 - 1988
(2007/10/02)
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- Biocidal compounds and compositions
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Biocidal compositions and methods of inhibiting biological growth employ, as the active agent, certain monocyclic and bicyclic heterocyclic compounds, some novel perse, of general formula I STR1 in which X is 0,1 or 2, R1, R2, R5 and R6 are a hydrogen atom, an alkyl radical containing up to 20 carbon atoms or an aryl radical; R3 is a hydrogen atom or a lower alkyl radical containing up to 6 carbon atoms; and R7 and R8, when taken separately, are hydrogen atoms or, when taken together, are STR2 in which R4 is a hydrogen atom, an alkyl radical containing up to 16 carbon atoms or an aryl radical. The preferred active agents generally have low solubility in sea water, are toxic to algal, barnacle or fungal growth, and are colorless. They may be used to form anti-fouling paints free from undesirable heavy metals or as anti-fungal additives in hydrocarbon fuels.
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- Dialkyl, Diaryl, and Alkyl Aryl Complexes of Ruthenium(II)
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Whereas HgR2 (R=methyl or aryl) converts trans-(Ru(CO)2Cl2(PMe2Ph)2) exclusively into (Ru(CO)2R(Cl)(PMe2Ph)2) and does not react with cis-(Ru(CO)2Cl2(PMe2Ph)2), LiR reacts with either isomer to yield (Ru(CO)2R2(PMe2Ph)2) and also catalyses conversion of the trans isomer into the cis.The initial attack by R- is belived to be on a carbonyl ligand.Treatment of (Ru(CO)2R(Cl)(PMe2Ph)2) with LiR' yields mixed complexes (Ru(CO)2R(R')(PMe2Ph)2).In all cases the two organic ligands are mutually cis.The dimethyl complex undergoes reversible carbonylation to form mono- and di-acetyl complexes, and (Ru(CO)2Me(Ph)(PMe2Ph)2) also forms an acetyl coplex, but aryl ligands are unaffected by treatment with CO.
- Saunders, David R.,Stephenson, Martin,Mawby, Roger J.
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p. 2473 - 2478
(2007/10/02)
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- Preliminary Studies of the Mechanism of Metal-Halogen Exchange. The Kinetics of Reaction of n-Butyllithium with Substituted Bromobenzenes in Hexane Solution
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Initial measurements of the rate of reaction of bromobenzene with n-butyllithium in hexane solution have shown the exchange to be first order in bromobenzene and first order in n-butyllithium, with an activation energy of 12 kcal mol-1 (52 kJ mol-1).A Hammett relationship for the reaction of substituted bromobenzenes with n-butyllithium suggests negative charge character in the transition state (ρ ca 2).The addition of a Lewis donor (p-methylanisole) to the hexane solution was found to result in an increase in the rate of exchange, but did not affect the Hammett reaction constant.Several transition-state structures are considered; available evidence suggests that the exchange may be concerted, with either a four-centered structure, or SN2-type attack of the n-butyl anion at the bromine of the aryl bromide
- Rogers, Harold R.,Houk, Janette
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p. 522 - 525
(2007/10/02)
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