1- Chloro-2-methylpropane Isobutyl chloride

Chloro 2 methylpropane Isobutyl chloride or 2 methylpropyl chloride 2 Chloro 2 methylpropane tert Butyl chloride or 1 1 dimethylethyl chloride... 

Chloro-2-methylpropane Isobutyl chloride or 2-methylpropyl chloride... 

There are three major limitations on the Friedel-Crafts alkylation. The first is the possibility for rearrangement of the alkyl group. Friedel-Crafts alkylation generates a carbocation, and as we have already seen in Section 6.3C, carbocations may rearrange to a more stable carbocation. For example, reaction of benzene with l-chloro-2-methylpropane (isobutyl chloride) gives only 2-methyl-2-phenylpropane (tert-butylbenzene). 

Selectivity is increased when the possibilities include the formation of a tertiary radical. Photochlorination of 2-methylpropane, for example, gives a 64 36 mixture of l-chloro-2-methylpropane (isobutyl chloride) and 2-chloro-2-methylpropane (/ r/-butyl chloride). The primary tertiary ratio is 64 36 = 1.78 (Fig. 11.47). 

Give an efficient synthesis of (2-methylpropyl)benzene (isobutylbenzene, the starting material for the preparation of ibuprofen see Exercise 16-10), starting from benzene. [Hint What would you expect as the major monosubstitution product of Friedel-Crafts alkylation of benzene with l-chloro-2-methylpropane (isobutyl chloride) ]... 

Isobutyl chloride (l-chloro-2-methylpropane) [513-36-0] n 1.398. Same methods as described under isoamyl chloride. 

Methylpropane l-Chloro-2-methylpropane (63%) (isobutyl chloride) 2-Chloro-2-methylpropane (37%) (rert-butyl chloride)... 

Look carefully at the reactions shown in the previous section. In each case, an unsymmetrically substituted alkene has given a single addition product, rather than the mixture that might have been expected. For example, 2-methylpropene might have reacted with HCI to give l-chloro-2-methyI-propane (isobutyl chloride) in addition to 2-chloro-2-methylpropane, but it didn t. We say that such reactions are regiospecific (ree-jee-oh-specific) when only one of two possible orientations of addition occurs. 

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