Methylated phenyl cation

Calculate energies for reaction of 2-methyl-2-propyl chloride (to 2-methyl-2-propyl cation), 2-phenyl-2-propyl chloride (to 2-phenyl-2-propyl cation) mdphenyl chloride (to phenyl cation). (The energy of chloride is given at right.) Assuming that reaction (1) is normal , what is the effect of a benzene ring Does it facilitate or hinder loss of chloride ... 

As illustrated in Scheme 5, ( )-31 directly gives cation 37 via phenyl participation, while (Z)-31 provides 38 more slowly via methyl participation. Cation 37 can further rearrange to more stable 38 by 1,2-hydride shift, but 38 cannot isomerize to less stable 37. As a result, ( )-31 can afford not only 33,35, and 36 but also 34, but (Z)-31 only gives 34 and 35 depending on the nucleophilicity of the solvent. The unrearranged product 32 is formed via inversion only from (Z)-3I in a more nucleophilic solvent. This must result directly from the SN2 reaction of (Z)-31. 

McCleland has reported that 3-phenylpropan-l-ol [125] and 3-(p-methyl-phenyl)propan-l-ol 99 [126] cyclize to chromans when oxidized by the radical anion SO4, generated by redox decomposition of S20 with Fe. The intermediate arene radical cation 100 is attacked by the nucleophilic hydroxy group. Whereas 1,6-cyclization yields 7-methylchroman 102, 1,5-cyclization with subsequent C-migration leads to the regioisomer 6-methylchroman 105. A dependence of the isomeric ratio and the combined yields to the pH value is determined. While 7-methylchroman 102 is the main product over a wide pH range, 6-methylchroman 105 is only formed at low pH. When the pH is lowered, the combined yields decrease due to the formation of an a-oxidized non-cyclized product. 

An unusual arrangement for three-coordinate iodine is found in the structure101 of the cation [Rh3 (/x-dpmp)2 (/x-I)2 (/i-CO)(CO)2]+ (where dpmp = bis[(diphenylphosphino)methyl]phenyl-... 

Two additional cationic complexes were recently reported, 163 and 164, prepared by the reaction of trimethylsilyl triflate with bis[2-((dimethylamino)methyl)phenyl]silane (165)... 

The disubstituted methyl isocyanide cations [CpM(CO)2(CNMe)2]+, M = Mo, W, have been obtained by methylation of the corresponding dicyanide anions, [CpM(CO)2(CN)2] (46). Direct interaction between phenyl isocyanide and CpMo(CO)3Cl causes total carbonyl displacement (lM). 

Dimethyl and methyl phenyl 4,4-dimethyl-2,6-dioxocyclohexylidene tellurium compounds transferred a methyl group to triethylamine, triphenylphosphane, tris[di-methylamino]phosphane, and triphenylarsane. The methyl onium cations were isolated as lelraphenylborates. The alkylidene organo telluronium intermediate was identified by 31P-NMR spectroscopy in the reaction of the ylide with tris[dimethylamino]phosphanc . 

Fluoride derivatives of palladium(II) and platinum(II), all of which are phosphine derivatives, can be most simply grouped into one of two subsections, namely neutral or cationic species. The neutral species are all of the form [MXF(PPh3)2] (M = Pd, Pt) where X can be Cl, Br, I, H, methyl, phenyl and C6F5. The synthetic route into these compunds involves either addition of HF to a metal phosphine dihalide or... 

In the gas phase, alkylation of five-membered heterocycles by alkyl cations usually occurs via the usual addition-elimination mechanism of aromatic electrophilic substitution. The phenyl cation behaves differently, however although its substrate discrimination is limited, in accord with its exceedingly high reactivity, it has marked selectivity for the a position, which does not conform with the hard character of this cation. It has, therefore, been suggested that an electron-transfer mechanism is followed this is thermodynamically allowed for the phenylium, and likewise for the methyl cation, but not for other alkyl cations (Scheme 28). This SET mechanism applies also for acyl cations [87]. 

These compounds include the following type of C,N-chelating ligands 2-[(dimethylamino)methyl]phenyl 40a-45 (54.114-117) [2-(dimethyla-mino)phenyl]methyl 46a-c, 47a-c (80) 8-dimethylamino-l-naphthyl 48 -50 (110) 2-[(dimethylamino)methyl]phenyl methyl 51,52 (118), 8-(dimethylamino)methyl-l-naphthyl, 53,54 (118), 2-(4,4-dimethyl-2-oxa-zoline)-5-(methyl)phenyl 55,56 (119) and 2-(phenylazo)phenyl 57a,57b (120,121). For some representative examples, the structure was unambiguously proven by an X-ray crystal structure determination 40c (115), 41b (114), 44b (116), 47b (80), 49 (96), 54 (118), 56 (119), 57a (121), and 57b (122). The last compound was obtained as an unexpected by-product from the reaction of 2,4-dinitrophenyldiazonium cation with (3-methoxy-phenyl)trimethyltin (120) ... 

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