- Synthesis, Characterization, and Reactivity Studies of Subphthalocyanine Boron Triflate
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The highly reactive subphthalocyanine boron triflate complex ((subPc)BOTf) was isolated and characterized by X-ray diffraction and spectroscopic methods. The combination of (subPc)BOTf and bis(trimethylsilyl)amide (LiHMDS) yielded a kinetically induced frustrated Lewis pair system capable of activating a variety of substrates such as ethers, amides, and ketones. These reactions demonstrate the high reactivity of (subPc)BOTf toward organic molecules.
- Wang, Zikuan,Fu, Xuefeng
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supporting information
p. 285 - 290
(2017/04/26)
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- The chemical behavior of the silaoxine C22H34OSi3 and silaazetidine C25H43NSi4 towards CO2
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When 4,4a-dihydro-3,3-dimethyl-1-phenyl-4,4-bis(trimethylsilyl)-3H-2-oxa-3-sila-naphthaline (silaoxine C22H34OSi3 (3); orthorhombic, space group Pna21, Z=4) was thermolized in a CO2 atmosphere, the co
- S?nger, Inge,Bolte, Michael,Lerner, Hans-Wolfram
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p. 1219 - 1224
(2016/12/09)
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- Indole synthesis: palladium-catalyzed C-H bond amination via reduction of nitroalkenes with carbon monoxide
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Nitroalkenes have been called 'chemical chameleons' due to their versatility in numerous synthetic transformations. Herein, we describe the first transition metal-catalyzed transformation of conjugated nitroalkenes into indoles. Under mild reaction condit
- Hsieh, Tom H.H.,Dong, Vy M.
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experimental part
p. 3062 - 3068
(2009/09/05)
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- Reactions of lithium hydridosilylamides with carbonyl compounds and mixtures of carbonyl compounds and chlorotrimethylsilane
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The lithium hydridosilylamides Me2(H)SiN(Li)R (1: R = CMe3, 2: R = SiMe3) were allowed to react either with the non-enolizable carbonyl compounds CH2=C(Me)CHO, PhCHO and Ph2CO followed by trapping with chlorotrimethylsilane (A), or with mixtures of these carbonyl compounds and chlorotrimethylsilane (B). In the second case the course of the reactions is determined by the carbonyl compound. The composition of the reaction mixtures is nearly the same according to A and B. Main products in the reactions with the aldehydes are the corresponding imines R1CH=NR R1 = CH2=C(Me), Ph) 3, 4, 8, 9 formed by addition of the hydridosilylamides to the C=O group of the aldehydes and subsequent LiOSiMe2H elimination. Partial hydrosilylation of the aldehydes by the hydridosilanolate followed by the trimethylsilylation yields the alkoxydisiloxanes R1CH2OSiMe2OSiMe3 6, 11. In some cases 2 partially reacts under hydrosilylation to give the alkoxydisilazanes R1CH2OSiMe2NHSiMe3 7, 12. The hydrosilylation is the preferred reaction of 1 and 2 with benzophenone. The compounds Ph2CHOSiMe2NHR 13, 14 are obtained. This difference in the reaction behaviour of 1 and 2 towards the aldehydes and benzophenone is mainly due to steric reasons. Depending on the conditions the imines Ph2C=NR 20, 21 may be formed. Ph2CHOSiMe2OSiMe3 (22) is a secondary product of imine formation. In all reactions of 1 and 2 with the carbonyl compounds the corresponding alkoxysilanes R1CH2OSiMe3 (5: R1 = CH2=C(Me), 6: R1 = Ph) and Ph2CHOSiMe3 (15) are generated. Compounds resulting from a reaction of 1 and 2 with chlorotrimethylsilane are produced to minor extent, but only if the molar ratio of amide to carbonyl compounds is not greater than one. The formation of a silanimine intermediate in reaction according to B is not observed.
- Schneider, Jan,Popowski, Eckhard,Fuhrmann, Hans
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p. 663 - 672
(2007/10/03)
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- On the Problem of the Intermediate Formation of Silanone R2Si=O by Reactions of Silenes with Dinitrogen Oxide
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The silaethene Me2Si=C(SiMe3)2 (1a; unstable; from 1a * Ph2C=MSiMe3 = 4) forms with N2O an unstable cycloadduct, which decomposes under isomerization or cleavage.It was not possible to decide clearly, whether the last reaction, which leads to (Me3Si)2CN2 and polymers with (Me2SiO)n groups, proceeds with intermediate formation of silanone Me2Si=O or not (no trapping product with Et3SiH, but with Me3SiCl).The silanimines Me2Si=NSitBu3 (2a; unstable; from 2a * tBu3SiN3 = 7) and tBu2Si=NSitBu3 (2b; metastable) form with N2O unstable cycloadducts, which, under participation of the silanimines, react into products (10) being composed of a molecular silanone and a molecule silanimine.As has been shown by trapping experiments with Et3SiH, Me3SiCl, or Me3SiOMe, latter reaction involves unstable free silanones Me2Si=O (3a) or tBuSi=O (3b) as intermediates. 3b, generated in benzene from 2b/NO2 in the presence of equimolar amounts of tetrahydrofuran (THF), obviously forms an adduct 3b*THF, which is trapped by excess 2b.When 3b is produced in THF as solvent, the silanone starts THF polymerization, indicating a high Lewis acidity of silanones.
- Wiberg, Nils,Preiner, Gerhard,Schurz, Klaus
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p. 1407 - 1412
(2007/10/02)
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- Reactivity of the Labile Silaethene Me2Si=C(SiMe3)2, Stored as Ph2C=NSiMe3 Adducts
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Silaethene Me2Si=C(SiMe3)2 (1), stored as Ph2C=NSiMe3 adducts and regenerated from the adducts at about 100 deg C as a reaction intermediate, combines with reactants a-b (e.g.HO-H, RO-H, RCOO-H, RS-H, RHN-H, Ph2CN-H, RO-SiR3, R2N-SiR3, Ph2CN-SiR3, Cl-GeR3, Cl-SnR3) with insertion into the a-b bond, with a=b (e.g.O=CPh2, Me3SiN=CPh2, CH2=CHOMe, cis-piperylene), a=b=c (e.g.RN=N=N, O=N=N), a=b-c=d (e.g. butadiene, isoprene, trans-piperylene, 2,3-dimethylbutadiene, cyclopentadiene, anthracene, benzophenone, N-trimethylsilylbenzophenoneimine) under -, - as well as -c ycloaddition and with a=b-c-H (e.g. propene, butenes, isoprene, 2,3-dimethylbutadiene, acetone) under ene reaction.According to relative reaction rates, insertion and -cycloadditions seem to proceed in two reaction steps, whereas -cycloadditions and ene reactions with organic dienes and enes obviously are one step reactions.For reactivities cf.Table I. - Key words: Silaethene Me2Si=C(SiMe3)2, Insertions, Cycloadditions, Relative Reactivities
- Wiberg, N.,Preiner, G.,Wagner, G.,Koepf, H.
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p. 1062 - 1074
(2007/10/02)
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- Storing of the Labile Silaethene Me2Si=C(SiMe3)2 with N-Trimethylsilyl-benzophenoneimine Ph2C=NSiMe3
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N-Trimethylsilyl-benzophenoneimine Ph2C=NSiMe3 is able to "store" the silaethene Me2Si=C(SiMe3)2 (1), produced from Me2SiF-CLi(SiMe3)2, under formation of a - and -cycloadduct (2, 3), respectively.Above 60 deg C (above 120 deg C) 2 or 3 by the way of 1 transform into 1:5 mixture of 2 and 3 (into a 1:1 mixture of the dimer of 1 and the insertion product of 1 into the SiN-bond of Ph2C=NSiMe3).In the presence of 2,3-dimethyl-1,3-butadiene (dmb), 2 or 3 form by way of the reaction of the intermediate 1 with dmb a -cycloadduct (75percent) and an ene reaction product (25percent).The rate constants of the first order decomposition of 2 or 3 in the presence of dmb (80 deg C, solvents like Et2O, C6H6) are in the order of 2 E-4 s-1 (τ1/2 ca. 1 h) and 3 E-5 s-1 (τ1/2 ca. 6 h), respectively. - Key words: Silaethene Me2Si=C(SiMe3)2, Ph2C=NSiMe3-adduct, Kinetic Studies
- Wiberg, Nils,Preiner, G.,Wagner, G.,Koepf, H.,Fischer, G.
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p. 1055 - 1061
(2007/10/02)
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- Storage of Silan- and Germanimines Me2E=NR (E = Si, Ge) by Way of Sila- or Germadihydrotetrazoles
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Silan- and germanimines Me2E=NR (1, 2) ntBu3-n, SiPh3, EMe2N(SiMe3)2> react with azidoalkanes or -silanes R'N3 ntBu3-n, SiPh3, SiMe2N(SiMe3)2> by cycloaddition to form sila- or germatetrazoles 5, 6 (in addition, insertion products of Me2E=NR in the R'N bond of the azides and others are formed in some cases).The sila- or germadihydrotetrazoles decompose at raised temperatures in a first-order reaction, reversing their formation by cycloreversion into azides R'N3 or RN3 and imines Me2E=NR or Me2E=NR' (rate constants: Table 1).Consequently, azides operate as stores for silan- and germanimines.The unsaturated systems are formed only as short-lived intermediates.Their stabilization, as a rule, takes place by dimerization and/or insertion of the imines into the RN or R'N bond of the azides, formed as well by thermolysis of dihydrotetrazoles.
- Wiberg, Nils,Karampatses, Petros,Kim, Chung-Kyun
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p. 1213 - 1222
(2007/10/02)
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- Adduct Formation and Reactivity of Silane- and Germaneimines Me2E=NR (E = Si, Ge)
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Silane- and Germaneimines Me2E=NR (E = Si, Ge; R = silyl), generated as reactive intermediates by thermal cycloreversion from cycloadducts of Me2E=C(SiMe3)2 or Me2E=NR with silyl azides RN3, combine with reactants a (e.g.NEtMe2) under addition (formation of adducts 7), with a-b under insertion into the a-b bond (formation 13-16), with a=b (e.g.RN=EMe2, O=CPh2) under cycloaddition (e.g. formation of 17, 18), with a=b=c (e.g.R'N=N=N) under cycloaddition (e.g. formation of 19, 20), and with a=b-c-H (e.g.CH2=CR-CH2-H, O=CMe-CH2-H) under ene reaction (formation of 21-24). cycloaddition of Me2Si=NR with organic 1,3-dienes (e.g.CH2=CR-CR=CH2, cyclopentadiene) is not observed.By comparison with ethenes Me2E=C(SiMe3)2, imines Me2E=NR have greater tendency for insertion and lesser tendency for cycloaddition; by comparison with silaneimines Me2Si=NR, germaneimines Me2Ge=NR are possibly less Lewis acidic.
- Wiberg, Nils,Preiner, Gerhard,Karampatses, Petros,Kim, Chung-Kyun,Schurz, Klaus
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p. 1357 - 1368
(2007/10/02)
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- UEBER DIE SI-N-BINDUNG XLIV. DIE UMSETZUNG VON BENZOPHENON MIT BIS- UND TRIS(TRIMETHYLSILYL)AMIN
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1,1,3-Triphenyl-1H-isoindole (I) is obtained in yields up to 66percent by reacting benzophenone with tris(trimethylsilyl)amine or with bis(trimethylsilyl)amine and chlorotrimethylsilane in the presence of catalytic amounts of a Lewis acid at 230-280 deg C in a sealed tube or with equimolar amounts of a Lewis acid at 210 deg C without using a sealed tube.At temperatures above 280 deg C the same reactions yiels mixtures of I with 1,2,3-triphenyl-2H-isoindole (II), whose fraction can reach 25percent of the isoindole mixture.Mechanistic investigations on the new isoindole synthesis indicated, that azaallenium cations are involved as intermediates.
- Ruehlmann, K.,Schilling, H.,Frey, H.,Paul, H.
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p. 277 - 284
(2007/10/02)
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- Reaktivitaet des Silaethens Me2Si=C(SiMe3)2: Thermolyse von (Me3Si)2(Me2XSi)CLi (X z. B. (PhO)2PO2) in Anwesenheit von Silaethen-Faengern
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Silaethene Me2Si=C(SiMe3)2 (1), generated as a reaction intermediate by the thermal elimination of LiX from Me2XSi-CLi(SiMe3)2, combines with the reactants a - b (e. g.Me3Si-Cl, Me3Si-OMe) with insertion in the a - b bond, with a = b - c - H (e. g.CH2=CMe
- Wiberg, Nils,Preiner, Gerhard,Schieda, Oswald
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p. 3518 - 3532
(2007/10/02)
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