What are the major and minor products obtained in the reaction of (E)-3-methyl-2-pentene and HBr?

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Answer 1 · 2015-06-28T20:14:02

The major product by far is 3-bromo-3-methylpentane; there may be a small amount of 2-methyl-3-bromopentane.

The structure of (#E#)-3-methylpent-2-ene is

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According to Markovnikov's rule, the #"H"^+# from #"HBr"# will add to #"C-2"# of the alkene and form a 3° carbocation at #"C-3"#.

The #"Br"^-# will add to #"C-3"# and form 3-bromo-3-methylpentane

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There may be a small amount of product formed when the #"H"^+# adds to #"C-3"# of the alkene to form the less stable 2° carbocation at #"C-2"#.

The #"Br"^-# will then add to #"C-2"# and form 2-bromo-3-methylpentane.

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