2.3- Dimethyl-2-butene hydrogen chloride addition

Addition of hydrogen chloride to 3,3-dimethyl-1-butene gives a... 

For example, addition of hydrogen chloride to 3,3-dimethyl-l-butene yields not only 2-chloro-3,3-dimethylbutane, but also 2-chloro-2,3-dimethylbutane ... 

PROBLEM 6.5 Addition of hydrogen chloride to 3,3-dimethyl-1-butene gives a mixture of two isomeric chlorides in approximately equal amounts. Suggest reasonable structures for these two compounds, and offer a mechanistic explanation for their formation. 

FIGURE 3.68 Addition of hydrogen chloride to 2,3-dimethyl-2-butene. 

The reaction of hydrogen chloride with a symmetrically substituted alkene such as 2,3-dimethyl-2-butene is relatively simple. Protonation is followed by chloride addition to give the alkyl chloride. There are no choices to be made about the position of protonation, and once the carbocation is made, chloride formation is easy to rationalize. What happens if the ends of the alkene are differently substituted In such an instance, two products are possible (Rg. 9.4). We discussed this question briefly in Chapter 3 (p. 137), and the answer is that it depends on how the ends of... 

We saw in Chapters 9 and 10 that polar additions to alkenes are bedetdled by hydride or alkyl shifts when there is a possibility of forming a more stable cation from a less stable one. A typical example, the polar addition of hydrogen chloride to 3,3-dimethyl-l-butene, is shown again in Figure 11.59. Yet free radical additions... 

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