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1.
S. Catak V. Aviyente T. Nugay 《Journal of polymer science. Part A, Polymer chemistry》2005,43(2):455-467
The reactivity of n‐butyllithium (n‐BuLi) toward pyridine derivatives (pyridine, pyridazine, pyrimidine, and 1,3,5‐triazine) was subjected to a computational study to determine the most suitable n‐BuLi/heterocyclic ring system as an initiator for the anionic polymerization of methyl methacrylate (MMA). These systems were suggested to prevent side reactions occurring through n‐BuLi attack on the carbonyl carbon of MMA by sterically blocking the initiator. The initiation reaction was modeled with the B3LYP methodology 6‐31+G*. Activation barriers were used to analyze the reactivity of each n‐BuLi/heterocyclic ring system. Computational results showed that n‐BuLi/triazine had a significantly lower activation barrier. Therefore, n‐BuLi/triazine was the suggested initiator system for the anionic polymerization of poly(methyl methacrylate). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 455–467, 2005 相似文献
2.
The Use of (−)‐Sparteine/Organolithium Reagents for the Enantioselective Lithiation of 7,8‐Dipropyltetrathia[7]helicene: Single and Double Kinetic Resolution Procedures
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Dr. Julien Doulcet Dr. G. Richard Stephenson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18677-18689
The effect of organolithium reagent (RLi: R=nBu, iPr, sBu, tBu), solvent (diethyl ether, diethyl ether/THF and MTBE), and stoichiometry on the (?)‐sparteine‐mediated silylation of 7,8‐dipropyltetrathia[7]helicene shows that, unusually, substantially more than 0.5 equivalent of RLi (R=iPr, sBu, tBu) and a large excess of (?)‐sparteine (R=nBu, sBu) is often needed to achieve substantial conversions and good ee values. With nBuLi, however, just one equivalent of the organolithium reagent is sufficient to obtain high conversions. Our best results were obtained using the convenient tBuLi/(?)‐sparteine adduct with which the need for a high (?)‐sparteine/RLi ratio can be avoided. Single‐ and double‐kinetic resolution (KR) procedures give enantiopure samples of 2‐trimethylsilyl‐ and 2,13‐di(trimethylsilyl)‐7,8‐dipropyltetrathia[7]helicene and two‐step double‐KR combining (?)‐sparteine/sBuLi and chiral formamides affords the synthetically valuable 2‐formyl‐7,8‐dipropyltetrathia[7]helicene. This is the first use of (?)‐sparteine for the enantioselective lithiation of helicenes and the first report of tBuLi outperforming sBuLi in a (?)‐sparteine‐mediated procedure. 相似文献
3.
Ryo Nadano Dr. Kohei Fuchibe Dr. Masahiro Ikeda Hiroki Takahashi Junji Ichikawa Prof. Dr. 《化学:亚洲杂志》2010,5(8):1875-1883
1‐(Trifluoromethyl)vinylation is accomplished in two protocols by the in situ generation of thermally unstable 3,3,3‐trifluoroprop‐1‐en‐2‐yllithium ( 1 ): 1) a rapid lithium–halogen‐exchange reaction of 2‐bromo‐3,3,3‐trifluoroprop‐1‐ene ( 2 ) takes effect with sec‐BuLi at ?105 °C to generate vinyllithium 1 , which reacts with more reactive electrophiles, such as aldehydes and N‐tosylimines before its decomposition, to afford 2‐(trifluoromethyl)allyl alcohols and N‐[2‐(trifluoromethyl)allyl] sulfoamides in good yield; 2) treatment of 2 with nBuLi at ?100 °C causes a slow lithium–halogen exchange of 2 , which gives rise to a mixture of 1 and nBuLi. Vinyllithium 1 is preferentially trapped with less reactive electrophiles, such as N,N‐dimethylamides in the presence of BF3?OEt2, to afford 1‐(trifluoromethyl)vinyl ketones in good yield. Versatility of the products toward syntheses of CF3‐containing ring‐fused cyclopentenones is also demonstrated by the Pauson–Khand reaction and the Nazarov cyclization. 相似文献
4.
María Casimiro Dr. Pascual Oña‐Burgos Dr. Jens Meyer Steffen Styra Dr. Istemi Kuzu Prof. Dr. Frank Breher Prof. Dr. Ignacio Fernández 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(2):691-701
2D 7Li,15N heteronuclear shift correlation through scalar coupling has successfully been applied to several lithium organyls consisting of polydentate N ligands such as N,N,N′,N′‐tetramethylethylenediamine (tmeda), N,N,N′,N′,N′′‐pentamethyldiethylentriamine (pmdta) and (?)‐sparteine. Structural insights on the conformation of benzyllithium ? pmdta ( 5 ) in a toluene solution and the strength of ion pairing in combination with PGSE NMR measurements, 1H,1H‐NOESY and 1H,7Li‐HOESY experiments are presented. By studying in detail the formation of 5 in solution, a transient species has been observed for the first time and assigned to a pre‐complex of nBuLi and pmdta. In addition, the solution behaviour of the complex formed between benzyllithium and (?)‐sparteine ( 8 ) has been studied by PGSE and multinuclear NMR spectroscopy. The straightforward synthesis and first applications in asymmetric lithiations are also reported, which show that the new system benzyllithium ? (?)‐sparteine ( 8 ) provide poorer enantioselective induction than the classical nBuLi ? (?)‐sparteine ( 6 ). The results were supported by deprotonation experiments confirming that the formation of 8 relies on two relevant factors, namely temperature and lithiating reagent. The existence of 8 may thus interfere with the asymmetric induction when the system nBuLi ? (?)‐sparteine is used in the enantioselective deprotonations of N‐Boc‐N‐(p‐methoxyphenyl)‐benzylamine conducted in toluene. 相似文献
5.
The n‐butyllithium (n‐BuLi)/N,N,N',N'‐tetrametylethylene‐diamine (TMEDA) system (the molar ratio of TMEDA to n‐BuLi higher than 4/4) has been found to polymerize 1,3‐cyclohexadiene (1,3‐CHD) to produce “living” polymer having narrow molecular weight distribution with well‐controlled polymer chain length. Binary and ternary block copolymers with narrow molecular weight distribution could be synthesized from 1,3‐cyclohexadiene, styrene, and butadiene with very high efficiency. These polymers and their hydrogenated derivatives have excellent thermal, mechanical, chemical, and optical properties for the new industrial materials. 相似文献
6.
The sequential reaction of the amino(trimethylsilyl)carbene complex [(CO)5W=C(NH2)C≡CSiMe3] ( 1 ) with nBuLi and [I‐Fe(CO)2Cp] affords the C(carbene)‐N bridged heterobinuclear complex [(CO)5W=C{NHFe(CO)2Cp}C≡CSiMe3] ( 2 ). Desilylation of 1 is achieved by treatment with KF in THF/MeOH. From the reaction of the resulting complex [(CO)5W=C(NH2)C≡CH] ( 3 ) with nBuLi and [I‐Fe(CO)2Cp] two binuclear WFe compounds in a ratio of approximately 1:1 are obtained: the C(carbene)‐C≡C bridged complex 4 and the C(carbene)‐N bridged complex 5 . Repetition of the deprotonation/metallation sequence yields the trinuclear WFe2 complex 6 . One Fe(CO)2Cp fragment in 6 is bonded to the amino group and the other one to the terminal carbon atom of the ethynyl substituent. The analogous reaction of 3 with nBuLi and [Br‐Ni(PMe2Ph)2Mes] gives a ca. 1:1 mixture of two heterobinuclear complexes ( 7 and 8 ). Complex 7 is bridged by the C(carbene)‐C≡C and complex 8 by the C(carbene)‐N fragment. Subsequent reaction of 7 with BuLi and [Br‐Ni(PMe2Ph)2Mes] finally affords the trinuclear WNi2 complex 9 related to 6 . The solid‐state structure of 2 is established by an X‐ray diffraction analysis. The spectroscopic data of the bi‐ and trinuclear complexes indicate electronic communication between the metal centers through the bridging group. 相似文献
7.
Matthew V. Joannou Brandon S. Moyer Matthew J. Goldfogel Prof. Simon J. Meek 《Angewandte Chemie (International ed. in English)》2015,54(47):14141-14145
A catalytic protocol for the diastereoselective synthesis of anti‐1,2‐hydroxyboronates is described. The process provides access to secondary alkyl organoborons. The deborylative 1,2‐addition reactions of alkyl 1,1‐diborons proceed in the presence of a silver(I) salt with either KOtBu or nBuLi as an activator. The catalytic diastereoselective protocol can be extended to aryl, alkenyl, and alkyl aldehydes with up to 99:1 d.r. 相似文献
8.
Bhaskar R. Aluri Mohammed Ghalib Markus K. Kindermann Peter G. Jones Joachim W. Heinicke 《Heteroatom Chemistry》2015,26(6):426-435
The reactivity of tBuLi (pentane) toward the N‐neopentyl‐substituted π‐excess P=CH–N heterocycle 1 depends on the solvent (tetrahydrofuran, diethyl ether, hexane, and toluene) and reaction conditions. Trapping of the resulting organolithium compounds with CO2/ClSiMe3, ClSiMe3, or EtI led to various products indicating CH lithiation ( 1a , b ), normal addition of tBuLi at the P=C bond (E/Z ‐2a , b ), inverse addition of the primary addition product 2Li at the P=C bond of a second molecule 1 , affording 3‐tert‐butyl‐2,2’‐bis(1,3‐benzazaphospholines) 3 , or inverse addition of tBuLi ( 4b,c ). The formation of 3 demonstrates a novel route to asymmetric heterocyclic 1,2‐diphosphine ligands. The structure elucidation of the new compounds is based on their 31P and 13C NMR data with conclusive chemical shifts and P–C coupling constants, that of the isolated PH‐functionalized diphosphine 3 on crystal structure analysis. 相似文献
9.
Insights into the Metalation of Benzene and Toluene by Schlosser’s Base: A Superbasic Cluster Comprising PhK,PhLi, and tBuOLi
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Dr. Christian Unkelbach Prof. Dr. Donal F. O'Shea Prof. Dr. Carsten Strohmann 《Angewandte Chemie (International ed. in English)》2014,53(2):553-556
The metalation of benzene by Schlosser’s base (nBuLi/tBuOK) occurs smoothly in THF at low temperatures to afford a discrete mixed‐metal Li2K4 cluster that contains phenyl anions and tert‐butoxide. The aggregate itself exhibits superbasic behavior by metalating toluene. The delocalized benzyl anion obtained this way π bonds to potassium counterions, thereby creating a 2D coordination polymer. 相似文献
10.
The Behavior of 2‐Substituted‐3‐hydroxyisoindolinones in the Reaction with sec‐Butyllithium
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This paper presents a dualistic behavior of 2‐substituted‐3‐hydroxyisoindolones in reactions with sec‐butyllithium (sec‐BuLi). 2‐tert‐Butyl‐3‐hydroxy‐2,3‐dihydro‐1H‐isoindol‐1‐one ( 1a ) treated with sec‐BuLi undergoes metalation at position 7. On the other hand, the reaction between 3‐hydroxy‐2‐phenyl‐2,3‐dihydroxyisoindol‐1‐one ( 1j ) and sec‐BuLi results in 3‐sec‐butyl‐2‐phenyl‐2,3‐dihydroisiondol‐1‐one ( 3j ). 相似文献
11.
One‐pot regioselective benzylation of pyrroles and indoles using zirconium tetrachloride is discussed. This has been achieved by in‐situ generation of di(1H‐pyrrol‐1‐yl)zirconium(IV) chloride and di(1H‐indol‐1‐yl)zirconium(IV) chloride. It was observed that benzylation reactions of these complexes using n‐BuLi occurred at C‐2 position for pyrrole and C‐3 for indole. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
12.
Bungo Ochiai Ikuyoshi Tomita Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2001,39(7):1016-1023
The anionic polymerization of derivatives of 4‐phenyl‐1‐buten‐3‐yne was carried out to investigate the effect of substituents on the polymerization behavior. The polymerization of 4‐(4‐fluorophenyl)‐1‐buten‐3‐yne and 4‐(2‐fluorophenyl)‐1‐buten‐3‐yne in tetrahydrofuran at −78 °C with n‐BuLi/sparteine as an initiator gave polymers consisting of 1,2‐ and 1,4‐polymerized units in quantitative yields with ratios of 80/20 and 88/12, respectively. The molecular weights of the polymers were controlled by the ratio of the monomers to n‐BuLi, and the distribution was relatively narrow (weight‐average molecular weight/number‐average molecular weight < 1.2), supporting the living nature of the polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1016–1023, 2001 相似文献
13.
《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(1):253-261
(R)‐[1‐(Dimethylamino)ethyl]benzene reacts with nBuLi in a 1:1 molar ratio in pentane to quantitatively yield a unique hetero‐aggregate ( 2 a ) containing the lithiated arene, unreacted nBuLi, and the complexed parent arene in a 1:1:1 ratio. As a model compound, [Li4(C6H4CH(Me)NMe2‐2)2(nBu)2] ( 2 b ) was prepared from the quantitative redistribution reaction of the parent lithiated arene Li(C6H4CH(Me)NMe2‐2) with nBuLi in a 1:1 molar ratio. The mono‐Et2O adduct [Li4(C6H4CH(Me)NMe2‐2)2(nBu)2(OEt2)] ( 2 c ) and the bis‐Et2O adduct [Li4(C6H4CH(Me)NMe2‐2)2(nBu)2(OEt2)2] ( 2 d ) were obtained by re‐crystallization of 2 b from pentane/Et2O and pure Et2O, respectively. The single‐crystal X‐ray structure determinations of 2 b – d show that the overall structural motifs of all three derivatives are closely related. They are all tetranuclear Li aggregates in which the four Li atoms are arranged in an almost regular tetrahedron. These structures can be described as consisting of two linked dimeric units: one Li2Ar2 dimer and a hypothetical Li2nBu2 dimer. The stereochemical aspects of the chiral Li2Ar2 fragment are discussed. The structures as observed in the solid state are apparently retained in solution as revealed by a combination of cryoscopy and 1H, 13C, and 6Li NMR spectroscopy. 相似文献
14.
Keiji Kanki Yoshihiko Misumi Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2002,40(8):1075-1080
Polymerization of phenylacetylene (PA) with [(cod)IrCl]2‐based catalysts (cod: 1,5‐cyclooctadiene) was examined. The [(cod)IrCl]2/n‐BuLi and [(cod)IrCl]2/Ph2C?C(Ph)Li systems induced the polymerization of PA to produce polymers with a number‐average molecular weight (Mn) of around several thousand in rather low yields. On the other hand, the catalyst composed of [(cod)IrCl]2, norbornadiene (nbd), Ph3P, and Ph2C?C(Ph)Li (molar ratio of 1:1:1.1:2) produced polymer in a high yield (ca. 80%) in toluene at 0 °C. The resulting polymer showed a bimodal gel permeation chromatographic profile (Mn = 209,000 and 4300; ratio: 81/19). On the basis of these findings, the presence of two active species, that is, Ir complexes with nbd and cod, are discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1075–1080, 2002 相似文献
15.
Thomas Pugh Andrew Kerridge Richard A. Layfield 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(14):4329-4332
Deprotonation of the yttrium–arsine complex [Cp′3Y{As(H)2Mes}] ( 1 ) (Cp′=η5‐C5H4Me, Mes=mesityl) by nBuLi produces the μ‐arsenide complex [{Cp′2Y[μ‐As(H)Mes]}3] ( 2 ). Deprotonation of the As H bonds in 2 by nBuLi produces [Li(thf)4]2[{Cp′2Y(μ3‐AsMes)}3Li], [Li(thf)4]2[ 3 ], in which the dianion 3 contains the first example of an arsinidene ligand in rare‐earth metal chemistry. The molecular structures of the arsine, arsenide, and arsinidene complexes are described, and the yttrium–arsenic bonding is analyzed by density functional theory. 相似文献
16.
Developing Lithium Chemistry of 1,2‐Dihydropyridines: From Kinetic Intermediates to Isolable Characterized Compounds
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Dr. David R. Armstrong Catriona M. M. Harris Dr. Alan R. Kennedy Dr. John J. Liggat Dr. Ross McLellan Prof. Robert E. Mulvey Matthew D. T. Urquhart Dr. Stuart D. Robertson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14410-14420
Generally considered kinetic intermediates in addition reactions of alkyllithiums to pyridine, 1‐lithio‐2‐alkyl‐1,2‐dihydropyridines have been rarely isolated or characterized. This study develops their “isolated” chemistry. By a unique stoichiometric (that is, 1:1, alkyllithium/pyridine ratios) synthetic approach using tridentate donors we show it is possible to stabilize and hence crystallize monomeric complexes where alkyl is tert‐butyl. Theoretical calculations probing the donor‐free parent tert‐butyl species reveal 12 energetically similar stereoisomers in two distinct cyclotrimeric (LiN)3 conformations. NMR spectroscopy studies (including DOSY spectra) and thermal volatility analysis compare new sec‐butyl and iso‐butyl isomers showing the former is a hexane soluble efficient hydrolithiation agent converting benzophenone to lithium diphenylmethoxide. Emphasizing the criticalness of stoichiometry, reaction of nBuLi/Me6TREN with two equivalents of pyridine results in non‐alkylated 1‐lithio‐1,4‐dihydropyridine?Me6TREN and 2‐n‐butylpyridine, implying mechanistically the kinetic 1,2‐n‐butyl intermediate hydrolithiates the second pyridine. 相似文献
17.
Dr. Thomas Pugh Dr. Andrew Kerridge Dr. Richard A. Layfield 《Angewandte Chemie (International ed. in English)》2015,54(14):4255-4258
Deprotonation of the yttrium–arsine complex [Cp′3Y{As(H)2Mes}] ( 1 ) (Cp′=η5‐C5H4Me, Mes=mesityl) by nBuLi produces the μ‐arsenide complex [{Cp′2Y[μ‐As(H)Mes]}3] ( 2 ). Deprotonation of the As? H bonds in 2 by nBuLi produces [Li(thf)4]2[{Cp′2Y(μ3‐AsMes)}3Li], [Li(thf)4]2[ 3 ], in which the dianion 3 contains the first example of an arsinidene ligand in rare‐earth metal chemistry. The molecular structures of the arsine, arsenide, and arsinidene complexes are described, and the yttrium–arsenic bonding is analyzed by density functional theory. 相似文献
18.
Hiroshi Takikawa Arata Nishii Hiromu Takiguchi Hirotoshi Yagishita Masato Tanaka Keiichi Hirano Masanobu Uchiyama Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(30):12440-12444
An intramolecular benzyne–phenolate [4+2] cycloaddition is reported. Benzyne precursors, having vicinal halogen‐sulfonate functionalities, linked with a phenol(ate) by various tether groups undergo efficient intramolecular [4+2] cycloaddition by treatment with either Ph3MgLi or nBuLi for halogen–metal exchange to form various benzobarrelenes. 相似文献
19.
This work confirmed a novel ligand in the anionic polymerization, lithium phenoxide, which helped to improve the controllability of the polymerization. The stability of n‐BuLi against THF at 0°C was effectively improved by adding lithium phenoxide. More than 60% n‐BuLi in THF was alive with the presence of lithium phenoxide after stirring at 0°C for 20 min, compared to 2% under same conditions but without lithium phenoxide. The propagation of polymerization of styrene (St) and methyl methacrylate (MMA) were retarded after adding lithium phenoxide. And by adding more than 10 fold lithium phenoxide, completed conversion was achieved in the polymerization of MMA in THF at 0°C. The lithium phenoxide showed both promoting and inhibiting effects in the polymerization of isoprene (Ip): it promoted the formation of 3,4‐structure, while mitigated the formation of 1,2‐ and 1,4‐structures. In general, the polymerization rate of Ip was promoted by lithium phenoxide. 相似文献
20.
A Boryl‐Substituted Diphosphene: Synthesis,Structure, and Reaction with n‐Butyllithium To Form a Stabilized Adduct by pπ‐pπ Interaction
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Shun‐suke Asami Masafumi Okamoto Dr. Katsunori Suzuki Prof. Dr. Makoto Yamashita 《Angewandte Chemie (International ed. in English)》2016,55(41):12827-12831
A boryl‐substituted diphosphene was synthesized through the nucleophilic borylation of PCl3 with a borylzinc reagent, followed by a reduction with Mg. A combined analysis of the resulting diboryldiphosphene by single‐crystal X‐ray diffraction, DFT calculations, and UV/Vis spectroscopy revealed a σ‐electron‐donating effect for the boryl substituent that was slightly weaker than that of the 2,4,6‐tri‐tert‐butylphenyl (Mes*) ligand. The reaction of this diboryldiphosphene with nBuLi afforded a boryl‐substituted phosphinophosphide that was, in comparison with the thermally unstable Mes*‐substituted diaryldiphosphene, stabilized by a π‐electron‐accepting effect of the boryl substituent. 相似文献