Question

Write a mechanism for the SN1 substitution of (2R)- 2 Bromohexane with Iodide ion and explain the expected stereochemical outcome.

Answer 1

Br above the Racemic mixture of products (2R)- 2-Bromohexane palne attack below the palne attack In the first step, (2R)- 2-Bromohexane forms a carbocation intermediate. Since carbocation is planar the incoming nucleophile (iodide ion) can attack either from above the plane or below the plane to give a racemic mixture (50:50) of products 50 50