45bE - Organic Chemistry (Mcmurry)

Question

How might you prepare each of the following molecules using a nucleophilic substitution reaction at some step?

Step-by-Step Solution

Answer

$C{H}_{3}Br+{}^{-}O-C{\left(C{H}_3\right)}_3\to C{H}_3-O-C{\left(C{H}_3\right)}_3+NaBr$

$C{H}_{3}OH+Cl-C{\left(C{H}_3\right)}_3\to C{H}_3-O-C{\left(C{H}_3\right)}_3+{\left(C{H}_3\right)}_{3}C=C{H}_2$

S N 2 reaction

It is a nucleophilic substitution reaction in which an old bond is broken and new bond is formed both processes occur simultaneously. Hence, it’s a single-step reaction.

The two reacting species are involved in the rate determining steps.

$C{H}_{3}Br+{}^{-}O-C{\left(C{H}_3\right)}_3\to C{H}_3-O-C{\left(C{H}_3\right)}_3+NaBr$

                                                   Substitution reaction 

E 2 reaction

It is a nucleophilic elimination reaction in which an old bond is broken and new bond is formed both the process occur simultaneously and no intermediate is formed.

Here, the carbon-hydrogen or halogen bond breaks to form a new double bond. Hence, it’s a single-step reaction.

$C{H}_{3}OH+Cl-C{\left(C{H}_3\right)}_3\to C{H}_3-O-C{\left(C{H}_3\right)}_3+{\left(C{H}_3\right)}_{3}C=C{H}_2$

Elimination reaction 

Formation of C H 3 - O - C C H 3 3

Here, the nucleophilic substitution occur where NaBr is produced and desired product is formed.

The two reacting species are involved in the rate determining steps.

$C{H}_{3}Br+{}^{-}O-C{\left(C{H}_3\right)}_3\to C{H}_3-O-C{\left(C{H}_3\right)}_3+NaBr$

                                                   Substitution reaction