catalysis tops that of the hitherto most active molecular group 2 metal catalysts. Depending on the substrate, two different catalytic cycles are proposed. A: a classical metal hydride cycle and B: the Ba metal cycle. The latter is proposed for substrates that are easily reduced by Ba0, that is, conjugated alkenes, alkynes, annulated rings, imines and pyridines. In addition, a mechanism in which Ba0 and BaH2
Un grand nombre d'hydrocarbures insatures ont ete reduits par les metaux alcalins dans NH 3 liquide et les intermediaires carbanioniques ont ete detectes in situ par RMN et RPE. Les substrats sont partages en 3 groupes differents: a) ceux qui persistent comme dianions; b) ceux qui sont protones par NH 3 pour donner des anions monohydro; c) ceux qui subissent d'autres etapes de protonation/transfert
Un Grand nombre d'hydrocarbures insatures ont ete reduits par les metaux alcalins dans NH 3liquide et les intermediaires carbanioniques ont ete 在原位检测到 RMN 和 RPE。Les substrats sont partages en 3 groupes differents: a) ceux qui persistent comme dianions; b) ceux qui sont protones par NH 3 pour donner des anions monohydro;c) ceux qui subissent d'autres etapes de protonation/transfert d'electrons pour
Dienophile cycloaddition to cycloheptatriene and related complexes of tricarbonyliron. X-Ray crystal structures of [Fe(CO)<sub>3</sub>(η<sup>4</sup>-C<sub>7</sub>H<sub>7</sub>CN)]·C<sub>2</sub>(CN)<sub>4</sub>and [ Fe(CO)<sub>3</sub>(η<sup>4</sup>-C<sub>7</sub>H<sub>7</sub>–C<sub>7</sub>H<sub>7</sub>)]
作者:Suman K. Chopra、Desmond Cunningham、Seamus Kavanagh、Patrick McArdle、Grainne Moran
DOI:10.1039/dt9870002927
日期:——
The rate of tetracyanoethene (tcne) addition to tricarbonyliron complexes of some substituted azepines and 1-cyanocycloheptatriene have been measured. Experimental support for a concerted mechanism for the cycloaddition of tcne to tricarbonyl(η4-cycloheptatriene) iron is provided by the high dienophile dependence of the observed reaction rate on chaning from tcne to tricyanoethene. Frontier orbital
Silicon modified birth reduction and reductive alkylation of polynuclear aromatics
作者:Z. Marcinow、D.K. Clawson、P.W. Rabideau
DOI:10.1016/s0040-4020(01)89490-4
日期:1989.1
regiochemistry, overreduction, and prevent bond cleavage during the metal/ammonia reduction of aromatic and polynuclear aromatic compounds. The trimethylsilyl group is then removed by tetrabutylammonium fluoride and replaced by either hydrogen or primary alkyl, the latter case representing overall reductive alkylation. Results are presented for naphthalene together with its 1-methyl, 2-methyl and 2-methoxy derivatives
Metal-free hydrogenation catalysis of polycyclic aromatic hydrocarbons
作者:Yasutomo Segawa、Douglas W. Stephan
DOI:10.1039/c2cc37190a
日期:——
The frustratedLewispair, B(C(6)F(5))(3)/Ph(2)PC(6)F(5), acts as an efficient catalyst for the hydrogenation of the polycyclic hydrocarbons including anthracene derivatives, tetracene and tetraphene, at 80 degrees C and 100 atm H(2) pressure via a mechanism involving protonation of polyaromatic species followed by hydride transfer.