# What is the product of the reaction of diol with tosyl chloride followed by lithium aluminum hydride?

This question is about the structure of products X and Y. According to me, the answer should be only A (as OTs will substitute on benzylic carbon).

But in the answer key, they have given B and D.

There are two replaceable $\ce{H}$s in the starting material, but only 1 equiv of $\ce{TsCl}$ is given. Thus, primary $\ce{-OH}$ will win the battle due to steric reasons, and therefore, B represent the intermediate product X. The second reaction is firstly acid-base reaction between secondary $\ce{-OH}$ and $\ce{H-}$, and then, nucleophilic substitution ($\mathrm{S_N}$2) reaction to replace $\ce{-OTs}$ group by $\ce{H-}$. That leaves D as the product Y, after acid workup.
• The faster reaction is acid-base reaction. Once, acetic $\ce{H}$ removed from $\ce{-OH}$, it is basically not removable. – Mathew Mahindaratne May 20 '18 at 6:56