41839-69-4Relevant academic research and scientific papers
The smaller, the better? How the aggregate size affects the reactivity of (trimethylsilyl)methyllithium
Knauer, Lena,Wattenberg, Jonathan,Kroesen, Ulrike,Strohmann, Carsten
, p. 11285 - 11291 (2019)
Weighting both the basicity and nucleophilicity of an organolithium compound is crucial for an effective use of these reagents in syntheses. To achieve this, an aggregate of optimal size and reactivity has to be formed by adding suitable donating agents. Against usual expectations, this is not inevitably the smallest possible aggregate. In this work, we show that the monomeric complex of (trimethylsilyl)methyllithium stabilized by the bidentate ligand (R,R)-TMCDA shows no significant reactivity. In contrast, two dimeric aggregates stabilized by monodentate quinuclidine were obtained, exhibiting enhanced reactivity compared to the parent compound and to the monomeric complex.
Increasing enantioselectivities and reactivities by stereochemical tuning: Fenchone-based catalysts in dialkylzinc additions to benzaldehyde
Goldfuss, Bernd,Steigelmann, Melanie,Rominger, Frank
, p. 1785 - 1792 (2000)
Trimethylsilyl substitutions of the fenchyl alcohols [(1R,2R,4S)-exo-(2- Ar)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol, Ar = 2-methoxyphenyl (1) and Ar = 2-(dimethylaminomethyl)phenyl (2)] yield the chiral ligands 3 [Ar = 2- methoxy-3(trimethylsilyl)phenyl
Aminoarenethiolate-copper(I)-catalyzed amination of aryl bromides
Jerphagnon, Thomas,Van Klink, Gerard P. M.,De Vries, Johannes G.,Van Koten, Gerard
, p. 5241 - 5244 (2007/10/03)
(Chemical Equation Presented) Aminoarenethiolate-copper(I) complexes are known to be efficient catalysts for carbon-carbon bond formation. Here, we show the first examples that these thiolate-copper(I) complexes are efficient for carbon-nitrogen bond formation reactions as well. N-Arylation of benzylamine and imidazole with bromobenzene was achieved either in NMP as solvent or under solvent-free conditions in the presence of 2.5 mol % of aminoarenethiolate- copper(I) complex only.
Selective intramolecular cleavage of the carbon-silicon bond by palladium salts
Valk, Jean-Marc,Boersma, Jaap,Koten, Gerard van
, p. 213 - 216 (2007/10/02)
Several (aryl)trimethylsilane derivatives containing a potentially intramolecularly coordinating dimethylaminomethyl group were prepared and treated with Li2PdCl4 or Pd(OAc)2.Highly selective cleavage of the aryl-C-Si bond took place to give the correspon
Chemical and photochemical approaches to amino(aryl) silylenes
Corriu, Robert,Lanneau, Gerard,Priou, Christian,Soulairol, Florence,Auner, Norbert,et al.
, p. 55 - 68 (2007/10/02)
Generation by two different methods of silylenes stabilized by o-amino(aryl) groups is reported.The halodemetallation of difluoro- or dichloro-silanes with Li metal or lithium-naphthalene gave the same product, a stabilized sila-ylide (hypercoordinated silylene).Intramolecular Lewis base stabilization is not sufficient to isolate a monomeric species.The silylenes, however, have been trapped with 2,3-dimethylbutadiene.An unexpected intramolecular rearrangement to silaacenaphthene has been observed in the case of a six-membered ring amino(aryl) coordinated silylene.Photolysis of o-1--2-benzene produced, among other products, Me3SiSiMe3 and the sila-ylide, which has been trapped with Et3SiH and dimethylbutadiene.Our mechanistic interpretation is supported by spectral observation of the photochemically generated reaction intermediates in a 3-methylpentane glass at low temperature. Key words: Silylene; Sila-ylide; Amino-aryl; Alkali metals; Stabilization; Photochemistry
Intramolecular Facilitation of Aryl-transfer from Tin in Palladium-catalysed Cross-coupling
Brown, John M.,Pearson, Mark,Jastrzebski, Johann T. B. H.,Koten, Gerard van
, p. 1440 - 1441 (2007/10/02)
A neighbouring tertiary amino-group in the organotin reagent accelerates the palladium-catalysed arylation of furoyl chloride by a hundredfold.
Organometallic Derivatives of Cyclopropanes
Mueller, Paul,Bernardinelli, Gerald,Jacquier, Yvan
, p. 1995 - 2008 (2007/10/02)
The tricarbonylchromium complex of cyclopropanaphthalene (3a) is deprotonated at C(1) with BuLi.Quenching of the resulting anion with MeI results in a 1:1 mixture of stereoisomeric methyl derivatives 6a and 6b.Peterson olefination of the bis-silylated complex 3b affords the complexed alkylidenecycloproparene 5 in low yield.The tricarbonylchromium complex of cyclopropaanthracene (10) is accessible via bis-hydro-desilylation of 9.Its X-ray structure is also reported.All attempts to synthesize a tricarbonylchromium complex of benzocyclopropene (11a) failed.
Coordinative Interactions in Chelated Complexes of Silicon, 9. On the Crystal Structure Determination and the Mechanism of Intramolecular Positional Exchange of Pentacoordinated Silicon
Klebe, Gerhard,Nix, Marianne,Hensen, Karl
, p. 797 - 808 (2007/10/02)
Crystal structure determination revealed trigonal-bipyramidal coordinated silicon in 2-methyl>pyridine (2b).The extended coordination is achieved by intramolecular Lewis acid-base interactions (coordinative Si...N bond: 197.4(6) pm Si-N "single" bond: 170.1(10) pm).Below - 10 deg C in solution, this geometry is confirmed by NMR spectroscopy.The NMR spectra of closely related Si complexes of benzyldimethylamine indicate isostructural arrangement around silicon at low temperature.In all compounds intramolecular rearrangements of substituents at silicon are detected which become more and more rapid with increasing temperature.At elevated temperatures the coordinative bond is unstable and the positional exchange of substituents is achieved through a rotation of the intermediate tetragonal silyl group.The equilibration barriers show that coordinative bonding has to be attributed to weak interaction in the present case.
