Chapter 23, Problem 23.33P

Interpretation Introduction

Interpretation:

The synthesis of given transformation without forming any para isomer is to be shown.

Concept introduction:

The carbonyl group is a meta director thus on reduction can be reduced to alkyl group which is ortho/para director. The reduction of carbonyl to alkyl is achieved by treatment of $\text{Zn(Hg)/HCl}$. The para position of alkyl group can be locked by sulfonation using ${\text{SO}}_{\text{3}}{\text{/H}}_{\text{2}}{\text{SO}}_{\text{4}}$, which can also be easily removed by desulfonation using ${\text{H}}_{\text{3}}{\text{O}}^{+}$. The Fridel-Craft acylation of para sulfonyl alkyl benzene gives at ortho position of alkyl group.