3-methyl-3-hexyl cation

Examine the geometry of 3-methyl-3-hexyl bromide, and assign the configuration (R or S) to the chiral atom. Examine the geometry of 3-methyl-3-hexyl cation. Is it chiral ... 

Neither methyl nor ethyl fluoride gave the corresponding cations when treated with SbFs. At low temperatures, methyl fluoride gave chiefly the methylated sulfur dioxide salt, (CH3OSO) ShF while ethyl fluoride rapidly formed the rert-butyl and ferf-hexyl cations by addition of the initially formed ethyl cation to ethylene molecules also formed ° At room temperature, methyl fluoride also gave the tert-butyl cation. In accord with the stability order, hydride ion is abstracted from alkanes by super acid most readily from tertiary and least readily from primary positions. 

Ethyl fluoride shows more tendency to ionize in antimony pentafluoride, than does methyl fluoride. The solutions in neat antimony pentafluoride are, however, not stable and a rapid formation of t-butyl and t-hexyl cations is observed. This observation indicates self alkylation of ethylene formed in equilibrium of equation (2). 

The difference in the free energies for the secondary and the tertiary 2-methyl-bicyclo[2,l,l]hexyl cations is 7.0-9.8 kcal/mole while that for 2-norbornyl ions it is 5.5 kcal/mole 236,298) fgj, cydopentyl it is g 12.5 kcal/mole... 

The difference between the sum of the chemical shifts of all the atoms of the 2-bicyclo[2,l,l]hexyl ion and the corresponding hydrocarbon is 297 ppm, i.e. by 100 ppm less than in the case of the 2-methyl-2-bicyclo[2,l,l]hexyl cation this points to a considerable nonclassical delocalization in the secondary ion... 

The protolytic oxidative condensation of methane in Magic Acid solution at 60 °C is evidenced by the formation of higher alkyl cations such as t-butyl and t-hexyl cations (equation 42). It is not necessary to assume a complete cleavage of [CH5] to a free, energetically unfavorable methyl cation. The carbon-carbon bond formation can indeed be visualized through reaction of the C—H bond of methane with the developing methyl cation. 

The l-methyl-2-trideuteriomethyl-2-bicyclo[2.1.1]hexyl cation [116] has a definite equilibrium isotope effect. The averaged C-1 and C-2 carbons show an isotope splitting of 46.5 ppm at -128°C. The carbon bonded to the CDs-group is shifted to higher field. The enthalpy difference (AH° = — 50 cal mol" per D) for the isotopic equilibrium was calculated from the temperature dependence of the equilibrium constant between... 

The C-nmr spectrum of [230] recorded by Olah et al. (1976b) was very much like its proton spectrum in that it consisted of only three signals, with a two carbon resonance at S 157.8 ppm. It was not possible to freeze out the static ion [30] or [233]. The 2-methyl- [234] and 2-phenyI-2-bicyclo[2.l.l]hexyl [235] cations were prepared from the corresponding alcohols. The H-nmr spectrum of [234] was found to be temperature dependent. At low temperature (—100°C) three non equivalent types of methylene protons were observed, but at higher temperatures they equilibrate with each other via 1,2-carbon shifts. By comparison of the C-chemical shifts of [234] with those of the... 

Figure 3.3 Synthesis of methacrylate random copolymers with cationic amphiphilic structures containing R hydrophobic groups (methyl, ethyl, butyl, hexyl and benzyl groups). AIBN azobisisobutylonitrile, RT room temperature and TFA trifluoroacetic acid. Reprodnced with permission from H. Takahashi,...

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