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1.
Bin Rao Liliang Wang Rei Kinjo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):237-241
A borane B(C6F5)3‐catalyzed metathesis reaction between the Si?C bond in the cyclic (alkyl)(amino)germylene (CAAGe) 1 and the Si?H bond in a silane (R3SiH; 2 ) is reported. Mechanistic studies propose that the initial step of the reaction involves Si?H bond activation to furnish an ionic species [ 1 ‐SiR3]+[HB(C6F5)3]?, from which [Me3Si]+[HB(C6F5)3]? and an azagermole intermediate are generated. The former yields Me3SiH concomitant with the regeneration of B(C6F5)3 whereas the latter undergoes isomerization to afford CAAGes bearing various silyl groups on the carbon atom next to the germylene center. This strategy allows the straightforward synthesis of eight new CAAGes starting from 1 . 相似文献
2.
Synthesis,Structure, and Reactivity of Diazene Adducts: Isolation of iso‐Diazene Stabilized as a Borane Adduct 下载免费PDF全文
Dipl.‐Chem. Fabian Reiß Prof. Dr. Axel Schulz Dr. Alexander Villinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11800-11811
This work describes the synthesis and full characterization of a series of GaCl3 and B(C6F5)3 adducts of diazenes R1?N?N?R2 (R1=R2=Me3Si, Ph; R1=Me3Si, R2=Ph). Trans‐Ph?N?N?Ph forms a stable adduct with GaCl3, whereas no adduct, but instead a frustrated Lewis acid–base pair is formed with B(C6F5)3. The cis‐Ph?N?N?Ph ? B(C6F5)3 adduct could only be isolated when UV light was used, which triggers the isomerization from trans‐ to cis‐Ph?N?N?Ph, which provides more space for the bulky borane. Treatment of trans‐Ph?N?N?SiMe3 with GaCl3 led to the expected trans‐Ph?N?N?SiMe3 ? GaCl3 adduct but the reaction with B(C6F5)3 triggered a 1,2‐Me3Si shift, which resulted in the formation of a highly labile iso‐diazene, Me3Si(Ph)N?N; stabilized as a B(C6F5)3 adduct. Trans‐Me3Si?N?N?SiMe3 forms a labile cis‐Me3Si?N?N?SiMe3 ? B(C6F5)3 adduct, which isomerizes to give the transient iso‐diazene species (Me3Si)2N?N ? B(C6F5)3 upon heating. Both iso‐diazene species insert easily into one B?C bond of B(C6F5)3 to afford hydrazinoboranes. All new compounds were fully characterized by means of X‐ray crystallography, vibrational spectroscopy, CHN analysis, and NMR spectroscopy. All compounds were further investigated by DFT and the bonding situation was assessed by natural bond orbital (NBO) analysis. 相似文献
3.
Masakazu Nishida Haruhiko Fukaya Yoshio Hayakawa Taizo Ono Kotaro Fujii Hidehiro Uekusa 《Helvetica chimica acta》2006,89(11):2671-2685
The reagent Me3Si(C6F5) was used for the preparation of a series of perfluorinated, pentafluorophenyl‐substituted 3,6‐dihydro‐2H‐1,4‐oxazines ( 2 – 8 ), which, otherwise, would be very difficult to synthesize. Multiple pentafluorophenylation occurred not only on the heterocyclic ring of the starting compound 1 (Scheme), but also in para position of the introduced C6F5 substituent(s) leading to compounds with one to three nonafluorobiphenyl (C12F9) substituents. While the tris(pentafluorophenyl)‐substituted compound 3 could be isolated as the sole product by stoichiometric control of the reagent, the higher‐substituted compounds 5 – 8 could only be obtained as mixtures. The structures of the oligo(perfluoroaryl) compounds were confirmed by 19F‐ and 13C‐NMR, MS, and/or X‐ray crystallography. DFT simulations of the 19F‐ and 13C‐NMR chemical shifts were performed at the B3LYP‐GIAO/6‐31++G(d,p) level for geometries optimized by the B3LYP/6‐31G(d) level, a technique that proved to be very useful to accomplish full NMR assignment of these complex products. 相似文献
4.
Functionalization of Intramolecular Frustrated Lewis Pairs by 1,1‐Carboboration with Conjugated Enynes 下载免费PDF全文
Dr. Andreas Feldmann Dr. Gerald Kehr Dr. Constantin G. Daniliuc Dr. Christian Mück‐Lichtenfeld Prof. Dr. Gerhard Erker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(35):12456-12464
The vicinal P/B frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 undergoes 1,1‐carboboration reactions with the Me3Si‐substituted enynes to give ring‐enlarged functionalized C3‐bridged P/B FLPs. These serve as active FLPs in the activation of dihydrogen to give the respective zwitterionic [P]H+/[B]H? products. One such product shows activity as a metal‐free catalyst for the hydrogenation of enamines or a bulky imine. The ring‐enlarged FLPs contain dienylborane functionalities that undergo “bora‐Nazarov”‐type ring‐closing rearrangements upon photolysis. A DFT study had shown that the dienylborane cyclization of such systems itself is endothermic, but a subsequent C6F5 migration is very favorable. Furthermore, substituted 2,5‐dihydroborole products are derived from cyclization and C6F5 migration from the photolysis reaction. In the case of the six‐membered annulation product, a subsequent stereoisomerization reaction takes place and the resultant compound undergoes a P/B FLP 1,2‐addition reaction with a terminal alkyne with rearrangement. 相似文献
5.
Jiliang Zhou Liu Leo Liu Levy L. Cao Douglas W. Stephan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5461-5466
Double chloride abstraction of Cp*AsCl2 gives the dicationic arsenic species [(η5‐Cp*)As(tol)][B(C6F5)4]2 ( 2 ) (tol=toluene). This species is shown to exhibit Lewis super acidity by the Gutmann–Beckett test and by fluoride abstraction from [NBu4][SbF6]. Species 2 participates in the FLP activation of THF affording [(η2‐Cp*)AsO(CH2)4(THF)][B(C6F5)4]2 ( 5 ). The reaction of 2 with PMe3 or dppe generates [(Me3P)2As][B(C6F5)4] ( 6 ) and [(σ‐Cp*)PMe3][B(C6F5)4] ( 7 ), or [(dppe)As][B(C6F5)4] ( 8 ) and [(dppe)(σ‐Cp*)2][B(C6F5)4]2 ( 9 ), respectively, through a facile cleavage of C?As bonds, thus showcasing unusual reactivity of this unique As‐containing compound. 相似文献
6.
Fine‐Tuning of Lewis Acidity: The Case of Borenium Hydride Complexes Derived from Bis(phosphinimino)amide Boron Precursors 下载免费PDF全文
Dr. Kuldeep Jaiswal Dr. Billa Prashanth Dr. Sanjay Singh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):11035-11041
Reactions of bis(phosphinimino)amines LH and L′H with Me2S ? BH2Cl afforded chloroborane complexes LBHCl ( 1 ) and L′BHCl ( 2 ), and the reaction of L′H with BH3 ? Me2S gave a dihydridoborane complex L′BH2 ( 3 ) (LH=[{(2,4,6‐Me3C6H2N)P(Ph2)}2N]H and L′H=[{(2,6‐iPr2C6H3N)P(Ph2)}2N]H). Furthermore, abstraction of a hydride ion from L′BH2 ( 3 ) and LBH2 ( 4 ) mediated by Lewis acid B(C6F5)3 or the weakly coordinating ion pair [Ph3C][B(C6F5)4] smoothly yielded a series of borenium hydride cations: [L′BH]+[HB(C6F5)3]? ( 5 ), [L′BH]+[B(C6F5)4]? ( 6 ), [LBH]+[HB(C6F5)3]? ( 7 ), and [LBH]+[B(C6F5)4]? ( 8 ). Synthesis of a chloroborenium species [LBCl]+[BCl4]? ( 9 ) without involvement of a weakly coordinating anion was also demonstrated from a reaction of LBH2 ( 4 ) with three equivalents of BCl3. It is clear from this study that the sterically bulky strong donor bis(phosphinimino)amide ligand plays a crucial role in facilitating the synthesis and stabilization of these three‐coordinated cationic species of boron. Therefore, the present synthetic approach is not dependent on the requirement of weakly coordinating anions; even simple BCl4? can act as a counteranion with borenium cations. The high Lewis acidity of the boron atom in complex 8 enables the formation of an adduct with 4‐dimethylaminopyridine (DMAP), [LBH ? (DMAP)]+[B(C6F5)4]? ( 10 ). The solid‐state structures of complexes 1 , 5 , and 9 were investigated by means of single‐crystal X‐ray structural analysis. 相似文献
7.
Dihydrogen Catalysis of the Reversible Formation and Cleavage of CH and NH Bonds of Aminopyridinate Ligands Bound to (η5‐C5Me5)IrIII 下载免费PDF全文
Dr. Ana Zamorano Dr. Nuria Rendón Dr. Joaquín López‐Serrano Dr. José E. V. Valpuesta Dr. Eleuterio Álvarez Prof. Dr. Ernesto Carmona 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2576-2587
This study focuses on a series of cationic complexes of iridium that contain aminopyridinate (Ap) ligands bound to an (η5‐C5Me5)IrIII fragment. The new complexes have the chemical composition [Ir(Ap)(η5‐C5Me5)]+, exist in the form of two isomers ( 1+ and 2+ ) and were isolated as salts of the BArF? anion (BArF=B[3,5‐(CF3)2C6H3]4). Four Ap ligands that differ in the nature of their bulky aryl substituents at the amido nitrogen atom and pyridinic ring were employed. In the presence of H2, the electrophilicity of the IrIII centre of these complexes allows for a reversible prototropic rearrangement that changes the nature and coordination mode of the aminopyridinate ligand between the well‐known κ2‐N,N′‐bidentate binding in 1+ and the unprecedented κ‐N,η3‐pseudo‐allyl‐coordination mode in isomers 2+ through activation of a benzylic C?H bond and formal proton transfer to the amido nitrogen atom. Experimental and computational studies evidence that the overall rearrangement, which entails reversible formation and cleavage of H?H, C?H and N?H bonds, is catalysed by dihydrogen under homogeneous conditions. 相似文献
8.
Tatiana D. Grayfer Alexander Yu. Makarov Irina Yu. Bagryanskaya Irina G. Irtegova Yuri V. Gatilov Andrey V. Zibarev 《Heteroatom Chemistry》2015,26(1):42-50
Although an interaction between hydrocarbon and fluorocarbon 1,3,2,4‐benzodithiadiazines ( 1 ) and P(C6H5)3 continuously produces chiral 1,2,3‐benzodithiadiazol‐2‐yl iminophosporanes ( 2 ; in this work, 5,7‐difluoro derivative 2a ) via 1:1 condensation, an interaction between 1 and other PR3 reagents gives different products. With R OC6H5 and both hydrocarbon and fluorocarbon 1 , only X=P(OC6H5)3 (X = S, O) were identified in the complex reaction mixtures by 13С and 31Р NMR and GC‐MS. With R = C6F5, no interaction with the archetypal 1 was observed but catalytic addition of atmospheric water to the heterocycle afforded 2‐amino‐N‐sulfinylbenzenesulfenamide ( 4 ). With electrophilic B(C6F5)3 instead of nucleophilic P(C6F5)3, only adduct H3N→B(C6F5)3 and a new polymorph of C6F5B(OH)2 were isolated and identified by X‐ray diffraction (XRD). A molecular structure of 2a was confirmed by XRD, and the π‐stacked orientation of one of phenyl groups and heterocyclic moiety was observed. This structure is in general agreement with that calculated at the RI‐MP2 level of theory, as well as at three different levels of DFT theory with the PBE and B3LYP functionals. Mild thermolysis of 2a in a dilute decane solution gave persistent 5,7‐difluoro‐1,2,3‐benzodithiazolyl ( 3a ) identified by EPR in combination with DFT calculations. 相似文献
9.
《Journal of polymer science. Part A, Polymer chemistry》2018,56(12):1308-1321
Vinylsilanes CH2CHSiR3 (R = Me, NMe2, OMe, OTMS) copolymerize with ethylene rapidly in the presence of catalytic amounts of [Cp′2ZrMe][MeB(C6F5)3] (Cp′ = η5‐C5Me5) ( I ) to give high molecular weight silyl‐functionalized polyethylene. The molecular weight of the polymer can be controlled by varying the comonomer concentration as well as the reaction temperature. Relatively low molecular weight polymer was produced at a higher silyl monomer concentration and a higher polymerization temperature. The incorporation of silyl monomer in the polymer is in the range of 0.1‐ 6.0%. On the other hands, catalysts [Cp2ZrMe][MeB(C6F5)3] (Cp′ = η5‐C5H5) ( II ) and [Cp″2ZrMe][MeB(C6F5)3] (Cp″ = η5‐1,2‐C5Me2H3) ( III ) show much lower activity. With the use of more coordinatively unsaturated constrained geometry catalysts (CGC), Me2Si(η5‐C5Me4)(NtBu)MMe][MeB(C6F5)3] ( IV , M = Zr; V , M = Ti), the silyl monomer incorporation in the polymer was increased to 40%. The Ti catalyst is more active and produces polymer with a higher molecular weight with a higher silyl monomer incorporation at 23 °C. The copolymerization of vinyltrimethylsilane with propylene was also investigated with these catalysts, yielding high silyl‐functionalized propylene copolymer/oligmer. The microstructure of the copolymers/oligomers has been thoroughly investigated by 1D and 2D NMR techniques (1H, 13C, NOE, DEPT, HETCOR, and FLOCK). The results show that the backbone of the copolymers/oligomers is essentially random. Several termination pathways have been identified. In particular, two unsaturated silyl terminations, cis and/or trans‐TMS CHCH , were identified with the constrained geometry catalysts. Their formation was rationalized based on transition state models. It was found that occasional 1,2‐insertion of either propylene or vinyltrimethylsilane into the chain propagation process has a high probability serving as the trigger for polymer chain termination via β‐H elimination. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1308–1321 相似文献
10.
Zhongbao Jian Prof. Dr. Dongmei Cui Prof. Dr. Zhaomin Hou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(9):2674-2684
A series of rare‐earth‐metal–hydrocarbyl complexes bearing N‐type functionalized cyclopentadienyl (Cp) and fluorenyl (Flu) ligands were facilely synthesized. Treatment of [Y(CH2SiMe3)3(thf)2] with equimolar amount of the electron‐donating aminophenyl‐Cp ligand C5Me4H‐C6H4‐o‐NMe2 afforded the corresponding binuclear monoalkyl complex [({C5Me4‐C6H4‐o‐NMe(μ‐CH2)}Y{CH2SiMe3})2] ( 1 a ) via alkyl abstraction and C? H activation of the NMe2 group. The lutetium bis(allyl) complex [(C5Me4‐C6H4‐o‐NMe2)Lu(η3‐C3H5)2] ( 2 b ), which contained an electron‐donating aminophenyl‐Cp ligand, was isolated from the sequential metathesis reactions of LuCl3 with (C5Me4‐C6H4‐o‐NMe2)Li (1 equiv) and C3H5MgCl (2 equiv). Following a similar procedure, the yttrium‐ and scandium–bis(allyl) complexes, [(C5Me4‐C5H4N)Ln(η3‐C3H5)2] (Ln=Y ( 3 a ), Sc ( 3 b )), which also contained electron‐withdrawing pyridyl‐Cp ligands, were also obtained selectively. Deprotonation of the bulky pyridyl‐Flu ligand (C13H9‐C5H4N) by [Ln(CH2SiMe3)3(thf)2] generated the rare‐earth‐metal–dialkyl complexes, [(η3‐C13H8‐C5H4N)Ln(CH2SiMe3)2(thf)] (Ln=Y ( 4 a ), Sc ( 4 b ), Lu ( 4 c )), in which an unusual asymmetric η3‐allyl bonding mode of Flu moiety was observed. Switching to the bidentate yttrium–trisalkyl complex [Y(CH2C6H4‐o‐NMe2)3], the same reaction conditions afforded the corresponding yttrium bis(aminobenzyl) complex [(η3‐C13H8‐C5H4N)Y(CH2C6H4‐o‐NMe2)2] ( 5 ). Complexes 1 – 5 were fully characterized by 1H and 13C NMR and X‐ray spectroscopy, and by elemental analysis. In the presence of both [Ph3C][B(C6F5)4] and AliBu3, the electron‐donating aminophenyl‐Cp‐based complexes 1 and 2 did not show any activity towards styrene polymerization. In striking contrast, upon activation with [Ph3C][B(C6F5)4] only, the electron‐withdrawing pyridyl‐Cp‐based complexes 3 , in particular scandium complex 3 b , exhibited outstanding activitiy to give perfectly syndiotactic (rrrr >99 %) polystyrene, whereas their bulky pyridyl‐Flu analogues ( 4 and 5 ) in combination with [Ph3C][B(C6F5)4] and AliBu3 displayed much‐lower activity to afford syndiotactic‐enriched polystyrene. 相似文献
11.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(17):4822-4826
The chlorination of Si−H bonds often requires stoichiometric amounts of metal salts in conjunction with hazardous reagents, such as tin chlorides, Cl2, and CCl4. The catalytic chlorination of silanes often involves the use of expensive transition‐metal catalysts. By a new simple, selective, and highly efficient catalytic metal‐free method for the chlorination of Si−H bonds, mono‐, di‐, and trihydrosilanes were selectively chlorinated in the presence of a catalytic amount of B(C6F5)3 or Et2O⋅B(C6F5)3 and HCl with the release of H2 as a by‐product. The hydrides in di‐ and trihydrosilanes could be selectively chlorinated by HCl in a stepwise manner when Et2O⋅B(C6F5)3 was used as the catalyst. A mechanism is proposed for these catalytic chlorination reactions on the basis of competition experiments and density functional theory (DFT) calculations. 相似文献
12.
Piano‐stool‐shaped platinum group metal compounds, stable in the solid state and in solution, which are based on 2‐(5‐phenyl‐1H‐pyrazol‐3‐yl)pyridine ( L ) with the formulas [(η6‐arene)Ru( L )Cl]PF6 {arene = C6H6 ( 1 ), p‐cymene ( 2 ), and C6Me6, ( 3 )}, [(η6‐C5Me5)M( L )Cl]PF6 {M = Rh ( 4 ), Ir ( 5 )}, and [(η5‐C5H5)Ru(PPh3)( L )]PF6 ( 6 ), [(η5‐C5H5)Os(PPh3)( L )]PF6 ( 7 ), [(η5‐C5Me5)Ru(PPh3)( L )]PF6 ( 8 ), and [(η5‐C9H7)Ru(PPh3)( L )]PF6 ( 9 ) were prepared by a general method and characterized by NMR and IR spectroscopy and mass spectrometry. The molecular structures of compounds 4 and 5 were established by single‐crystal X‐ray diffraction. In each compound the metal is connected to N1 and N11 in a k2 manner. 相似文献
13.
Gabriele Albertin Stefano Antoniutti Jesús Castro Francesca Sibilla 《无机化学与普通化学杂志》2019,645(8):638-644
Imine complexes [IrCl(η5‐C5Me5){κ1‐NH=C(H)Ar}{P(OR)3}]BPh4 ( 1 , 2 ) (Ar = C6H5, 4‐CH3C6H4; R = Me, Et) were prepared by allowing chloro complexes [IrCl2(η5‐C5Me5){P(OR)3}] to react with benzyl azides ArCH2N3. Bis(imine) complexes [Ir(η5‐C5Me5){κ1‐NH=C(H)Ar}2{P(OR)3}](BPh4)2 ( 3 , 4 ) were also prepared by reacting [IrCl2(η5‐C5Me5){P(OR)3}] first with AgOTf and then with benzyl azide. Depending on the experimental conditions, treatment of the dinuclear complex [IrCl2(η5‐C5Me5)]2 with benzyl azide yielded mono‐ [IrCl2(η5‐C5Me5){κ1‐NH=C(H)Ar}] ( 5 ) and bis‐[IrCl(η5‐C5Me5){κ1‐NH=C(H)Ar}2]BPh4 ( 6 ) imine derivatives. In contrast, treatment of chloro complexes [IrCl2(η5‐C5Me5){P(OR)3}] with phenyl azide C6H5N3 gave amine derivatives [IrCl(η5‐C5Me5)(C6H5NH2){P(OR)3}]BPh4 ( 7 , 8 ). The complexes were characterized spectroscopically (IR, NMR) and by X‐ray crystal structure determination of [IrCl(η5‐C5Me5){κ1‐NH=C(H)C6H4‐4‐CH3}{P(OEt)3}]BPh4 ( 2b ). 相似文献
14.
Boron Lewis Acid‐Catalyzed Hydroboration of Alkenes with Pinacolborane: BArF3 Does What B(C6F5)3 Cannot Do!
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Dr. Qin Yin Dr. Hendrik F. T. Klare Prof. Dr. Martin Oestreich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(39):13840-13844
The transition‐metal‐free hydroboration of various alkenes with pinacolborane (HBpin) initiated by tris[3,5‐bis(trifluoromethyl)phenyl]borane (BArF3) is reported. The choice of the boron Lewis acid is crucial as the more prominent boron Lewis acid tris(pentafluorophenyl)borane (B(C6F5)3) is reluctant to react. Unlike B(C6F5)3, BArF3 is found to engage in substituent redistribution with HBpin, resulting in the formation of ArFBpin and the electron‐deficient diboranes [H2BArF]2 and [(ArF)(H)B(μ‐H)2BArF2]. These in situ‐generated hydroboranes undergo regioselective hydroboration of styrene derivatives as well as aliphatic alkenes with cis diastereoselectivity. Another ligand metathesis of these adducts with HBpin subsequently affords the corresponding HBpin‐derived anti‐Markovnikov adducts. The reactive hydroboranes are regenerated in this step, thereby closing the catalytic cycle. 相似文献
15.
Han Shen Ian M. Steele Richard F. Jordan 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):m405-m406
In the crystal structure of the title compound, [LiPd2Cl4(C12H12N2)2](C24F20B)·1.196CD2Cl2 or [{(Me2bipy)PdCl2}2(μ‐Li)]+·B(C6F5)4−·1.196CD2Cl2 (Me2bipy is 4,4′‐dimethyl‐2,2′‐bipyridine), an Li+ cation is stabilized by complexation with two (Me2bipy)PdCl2 units through weak Li—Cl interactions. This compound is thus a rare example of a complex that exhibits an arrested Cl− abstraction. 相似文献
16.
Leonid I. Goryunov Vitalij D. Shteingarts Joseph Grobe Bernt Krebs Michael U. Triller 《无机化学与普通化学杂志》2002,628(8):1770-1779
Trimethylsilyldimethylarsane Me3SiAsMe2 was used as a reagent for the substitution of fluorine in polyfluoroarenes C6F5X (X = F, H, Cl) and C5NF5 by the Me2As group. The reactions occur between 50 — 180 °C, either in benzene or without solvent, to give as a rule 4‐X‐1‐(dimethylarsano)tetrafluorobenzenes XC6F4AsMe2, ( 1—3 ) and 4‐dimethylarsano‐tetrafluoropyridine C5NF4AsMe2 ( 4 ), respectively, in yields between 43 and 94 %. In the case of C6F6, also double substitution is observed affording 1, 4‐bis(dimethylarsano)tetrafluorobenzene 5 in addition to the monosubstituted derivative. The time and temperature dependencies of the reactions increase in the sequence: C6F6< C6F5H < C6F5Cl < C5NF5. The arsanes 1 and 4 were transformed to the potentially valuable bidentate ligands 1‐(dimethylarsano)‐4‐(dimethylphosphano)tetrafluorobenzene 6 and 4‐(dimethylarsano)‐2‐(dimethylphosphano)trifluoropyridine 8 by reaction with trimethylsilyl‐dimethylphosphane Me3SiPMe2. 6 reacts with oxygen to yield the corresponding phosphane oxide 7 . Trimethylsilyl‐dimethylamine Me3SiNMe2 also was successfully tested as a reagent for the dimethylamination of polyfluoroarenes C6F5X [X = F, H, Cl, CF3, P(S)Me2], 1‐P(S)Me2‐4‐H‐C6F4 and 4‐X‐C5NF4 [X = F, PMe2, P(S)Me2]. Sulfuration of the new Me2P derivatives 8 and 20 leads to the corresponding thiophosphanes 9 and 21 (Schemes 2 and 3). Furthermore, the recently reported very efficient one‐pot synthesis of Me2P substituted polyfluoroarenes (e.g. XC6F4PMe2 with X = F, Me2PC6F4) was extended to the preparation of Me2As and MeS derivatives of pentafluoropyridine using a mixture of Me3SnH, As2Me4 (or S2Me2) and C5NF5 as precursors for the one‐pot reaction. The expected products 4‐(dimethylarsano)tetrafluoropyridine 4 and 4‐(methylthio)tetrafluoropyridine 22 , respectively, were obtained in 84 and 82 % isolated yields. The novel compounds were characterized by spectroscopic (NMR, MS) and analytical data. Compounds 5 , 7 , 9 and 21 could be isolated in form of single crystals and their structures have been studied by X‐ray diffraction. 相似文献
17.
Qing‐Xia Zhang Yao Li Jie Wang Chen Yang Cheng‐Jun Liu Xin Li Jin‐Pei Cheng 《Angewandte Chemie (International ed. in English)》2020,59(11):4550-4556
The enantioselective ketimine–ene reaction is one of the most challenging stereocontrolled reaction types in organic synthesis. In this work, catalytic enantioselective ketimine–ene reactions of 2‐aryl‐3H‐indol‐3‐ones with α‐methylstyrenes were achieved by utilizing a B(C6F5)3/chiral phosphoric acid (CPA) catalyst. These ketimine–ene reactions proceed well with low catalyst loading (B(C6F5)3/CPA=2 mol %/2 mol %) under mild conditions, providing rapid and facile access to a series of functionalized 2‐allyl‐indolin‐3‐ones with very good reactivity (up to 99 % yield) and excellent enantioselectivity (up to 99 % ee). Theoretical calculations reveal that enhancement of the acidity of the chiral phosphoric acid by B(C6F5)3 significantly reduces the activation free energy barrier. Furthermore, collective favorable hydrogen‐bonding interactions, especially the enhanced N?H???O hydrogen‐bonding interaction, differentiates the free energy of the transition states of CPA and B(C6F5)3/CPA, thereby inducing the improvement of stereoselectivity. 相似文献
18.
Cooperative Lewis Acid/Cp*CoIII Catalyzed C−H Bond Activation for the Synthesis of Isoquinolin‐3‐ones 下载免费PDF全文
Dr. Ju Hyun Kim Steffen Greßies Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2016,55(18):5577-5581
A facile route toward the synthesis of isoquinolin‐3‐ones through a cooperative B(C6F5)3‐ and Cp*CoIII‐catalyzed C?H bond activation of imines with diazo compounds is presented. The inclusion of a catalytic amount of B(C6F5)3 results in a highly efficient reaction, thus enabling unstable NH imines to serve as substrates. 相似文献
19.
Andrea Ravasio Laura Boggioni Incoronata Tritto Cristina D'arrigo Angelo Perico Julia Hitzbleck Jun Okuda 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5709-5719
The in situ synthesis of ethylene‐co‐norbornene copolymers/multi‐walled carbon nanotubes (MWNTs) nanocomposites was achieved by rare‐earth half‐sandwich scandium precursor [Sc(η5‐C5Me4SiMe3)(η1‐CH2SiMe3)2(THF)] (1) activated by [Ph3C][B(C6F5)4], through a non‐PFT (Polymerization Filling Technique) approach. MWNTs nanocomposites with low aluminum residue were obtained with excellent yields even though small amounts of triisobutylaluminium were needed as scavenger to prevent catalyst poisoning by MWNT impurities. MWNT bundles were disaggregated and highly coated with Poly(ethylene‐co‐norbornene) [P(E‐co‐N)] as revealed by transmission electron microscopy. Interestingly, P(E‐co‐N) copolymers showed Tg over 130 °C as well as norbornene content over 50 mol %; both values were higher than those obtained by the cationic active species in 1 /[Ph3C][B(C6F5)4]. A series of copolymerization reactions by 1 /[Ph3C][B(C6F5)4]/AliBu3 without MWNTs produced copolymers with the same unexpected features. The NMR analysis revealed the presence of rac‐ENNE and rac‐ENNNE sequences. Thus, AliBu3 changed the stereoirregular alternating copolymer microstructure produced by 1 /[Ph3C][B(C6F5)4]. We conclude that AliBu3 is not only a scavenger for CNT impurities, but it reacts with the THF ligand to give coordinatively unsaturated active species. Finally, P(E‐co‐N)/MWNT masterbatches were mixed with commercial TOPAS to produce cyclic olefin copolymer nanocomposites with excellent dispersion of filler. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5709–5719, 2009 相似文献
20.
Unexpected Reduction of [Cp*TaCl4(PH2R)] (R = But, Cy, Ad, Ph, 2,4,6‐Me3C6H2; Cp* = C5Me5) by Reaction with DBU – Molecular Structure of [(DBU)H][Cp*TaCl4] (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) [Cp*TaCl4(PH2R)] (R = But, Cy, Ad, Ph, 2,4,6‐Me3C6H2 (Mes); Cp* = C5Me5) react with DBU in an internal redox reaction with formation of [(DBU)H][Cp*TaCl4] ( 1 ) (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) and the corresponding diphosphane (P2H2R2) or decomposition products thereof. 1 was characterised spectroscopically and by crystal structure determination. In the solid state, hydrogen bonding between the (DBU)H cation and one chloro ligand of the anion is observed. 相似文献