4926-90-3Relevant academic research and scientific papers
Radical Cations of Cyclohexanes Alkyl-substituted on One Carbon: An ESR Study of the Jahn-Teller Distorted HOMO of Cyclohexane
Shiotani, Masaru,Lindgren, Mikael,Ohta, Nobuaki,Ichikawa, Takahisa
, p. 711 - 719 (2007/10/02)
Cation radicals of cyclohexanes alkyl-substituted on one carbon have been stabilized in perfluoromethylcyclohexane and other halocarbon matrices at 4.2 K and studied by means of ESR spectroscopy.It was found that all have an electronic ground state resembling the 2Ag state of the cyclohexane cation, one of the possible states following a Jahn-Teller distortion of the D3d cyclohexane chair structure.The cations can be classified into two groups depending on the substituted alkyl group.To the first group belong the cations with a methyl group or a primary carbon (ethyl, n-propyl or isobutyl group) attached to the ring.The disubstituted cyclohexane cations of 1,1-dimethylcyclohexane and 1-methyl-1-ethylcyclohexane were also found to have a similar structure.The ESR spectra are characterized by a 1:2:1 three-line pattern with the hyperfine (hf) splitting due to two magnetically equivalent equatorial ring hydrogens.The magnitude of the splitting was found to depend on the size and number of substituents, ranging from 74 G (methylcyclohexane.+) to 55 G (isobutylcyclohexane.+).An additional doublet, 17-34 G, due to a hydrogen on the substituent could be detected in certain cases.Such hydrogens are axial with one of the elongated C-C bonds in the ring structure which contains a relatively large fraction of the unpaired electron.It follows that the substituents are located asymmetrically with respect to an ag-like SOMO in the ring.In the second group a secondary or tertiary carbon connects the substituent to the ring, such as an isopropyl or tert-butyl group.The largest hf splittings are ca. 30 G in magnitude, due to certain hydrogens on the substituent which are axial with respect to the cyclohexyl bond.It follows that an ag-like SOMO in the ring here is symmetrically arranged with respect to the position of the substituent.Hyperconjugation is the dominating mechanism for the spin transfer in all cations reported in this study.
IONIC ALKYLATION OF TERTIARY ALKYL HALIDES WITH TETRAALKYLSILANES
Bolestova, G. I.,Parnes, Z. N.
, p. 32 - 36 (2007/10/02)
In the reaction of tertiary alkyl halides with tetraethyl-, tetrapropyl-, tetrabutyl-, and tetraamylsilane in the presence of AlX3 the halogen atom is substituted by the alkyl group with the formation of the corresponding saturated hydrocarbons containing a quaternary carbon atom.As a result of the hydride mobility of the β-hydrogen atom in the tetraalkylsilane ionic hydrogenolysis of the substrate occurs in addition to alkylation, and the degree of hydrogenolysis depends on the alkyl substituent in the silane.
IONIC HYDROMETHYLATION OF OLEFINS BY THE (CH3)4Si-HCl-AlCl3 SYSTEM
Bolestova, G. I.,Parnes, Z. N.,Kursanov, D. N.
, p. 2175 - 2179 (2007/10/02)
The ionic hydromethylation of olefins with the (CH3)4Si-HCl-AlCl3 system was realized for the first time.A method was developed on the basis of this system for the production of high yields of difficultly obtainable saturated hydrocarbons with a quaternary carbon atom (including bicyclic compounds with an angular methyl group) from acyclic, monocyclic, and bicyclic olefins.
