Ru(II)-Catalyzed Cycloadditions of 1,6-Heptadiynes with Alkenes: New Synthetic Potential of Ruthenacyclopentatrienes as Biscarbenoids in Tandem Cyclopropanation of Bicycloalkenes and Heteroatom-Assisted Cyclocotrimerization of 1,6-Heptadiynes with Heterocyclic Alkenes
derivatives, furnishes the 1:2adducts between the diynes and two molecules of the bicycloalkenes together with common [2 + 2 + 2] cyclocotrimerization products. The structure of a representative tandem 1:2adduct between dimethyl dipropargylmalonate and 2,4-dimethylbicyclo[3.2.1]oct-6-en-3-one was unequivocally determined by X-ray analysis and was concluded to involve an unusual 1,2-dicyclopropylcyclopentene
Activation of unsaturated substrates by cobalt complexes. Crystal structure and reactivity of a complex of octacarbonyl dicobalt with N-methylbis(α,α-dimethylpropargyl)amine
作者:Luigi Pietro Battaglia、Daniele Delledonne、Mario Nardelli、Giovanni Predieri、Gian Paolo Chiusoli、Mirco Costa、Corrado Pelizzi
DOI:10.1016/0022-328x(89)88055-6
日期:1989.3
A new complex of octacarbonyl dicobalt with N-methyl(α,α-dimethylpropargyl)amine was prepared and characterized by spectroscopic and X-ray diffraction methods. Each triple bond is coordinated to a hexacarbonyldicobalt fragment and each metal shows a pseudo-octahedral geometry. The structure of the free ligand having NH in place of N-methyl has also been determined for comparison.
Grigg, Ronald; Scott, Ronald; Stevenson, Paul, Journal of the Chemical Society. Perkin transactions I, 1988, p. 1357 - 1364
作者:Grigg, Ronald、Scott, Ronald、Stevenson, Paul
DOI:——
日期:——
Switching from Dimerization to Cyclotrimerization Selectivity by FeCl<sub>3</sub> in the Y[N(TMS)<sub>2</sub>]<sub>3</sub>-Catalyzed Transformation of Terminal Alkynes: A New Strategy for Controlling the Selectivity of Organolanthanide-Based Catalysis
作者:Xiuli Bu、Zhengxing Zhang、Xigeng Zhou
DOI:10.1021/om100402h
日期:2010.8.23
Y[N(TMS)(2)](3)/FeCl3 has been found to be an efficient bimetallic catalyst system for the cyclotrimerization of terminal alkynes, which cannot be achieved by either trivalent iron or trivalent lanthanide catalysts. Furthermore, this reaction also occurs efficiently in the presence of Fe[N(TMS)(2)](3) and YCl3. Both aromatic and aliphatic alkynes are compatible with this catalytic system. It is postulated that the catalytic cyclotrimerization proceeds through a tandem intermolecular diinsertion of alkynes into the yttrium-alkynyl bond and intramolecular electrophilic addition of a pi-coordinated alkyne moiety, and the pi-coordination of Fe3+ to alkyne may play an important role in controlling the insertion degree of advancement and selectivity. The observed catalytic reaction is sharply in contrast with the cyclotrimerization of alkynes, known to proceed through a typical metallacyclopentadiene intermediate.
Selective Oligomerization and [2 + 2 + 2] Cycloaddition of Terminal Alkynes from Simple Actinide Precatalysts
作者:Rami J. Batrice、Jamie McKinven、Polly L. Arnold、Moris S. Eisen
DOI:10.1021/acs.organomet.5b00455
日期:2015.8.24
A catalyzed conversion of terminal alkynes into dimers, trimers, and trisubstituted benzenes has been developed using the actinide amides U[N(SiMe3)(2)](3) (1) and [(Me3Si2N](2)An[kappa(2)-(N,C)-CH2Si(CH3)N(SiMe3)] (An = U (2), Th (3)) as precatalysts. These complexes allow for preferential product formation according to the identity of the metal and the catalyst loading. While these complexes are known as valuable precursors for the preparation of various actinide complexes, this is the first demonstration of their use as catalysts for C-C bond forming reactions. At high uranium catalyst loading, the cycloaddition of the terminal alkyne is generally preferred, whereas at low loadings, linear oligomerization to form enynes is favored. The thorium metallacycle produces only organic enynes, suggesting the importance of the ability of uranium to form stabilizing interactions with arenes and related pi-electron-containing intermediates. Kinetic, spectroscopic, and mechanistic data that inform the nature of the activation and catalytic cycle of these reactions are presented.