Question

Which is the best method the conversion of (A) pentan-2-ol to 3-bromopentane (B) ?
A.
B.
C. (A) `overset(HBr)rarr` (B)
D. Both (a) and (b)

Answer 1

Correct Answer - D
Method (c ) would give rearranged product also. It would give a mixture of 2-bromo and 3-bromo and 3-bromo pentane. In methods (a) and (b), no rerrangement occurs and it gives (B) exclusively. The tosyl group, a good leaving group, is then easily displaced by reaction with `Br^(-)` in an `SN^(2)` reaction.