Question

Which of the following would not give 2-phenylbutane as the major product in a Friedel-Crafts alkylation reaction ?

• A. 1-butene + $HF$
• B. 2-butanol + $H_2SO_4$
• C. Butanoyl chloride + $AlCl_3$ then $Zn, HCl$
• D. Butyl choloride + $AlCl_3$

Answer 1

Answer: (C)

The Friedal-crafts alkylation reaction will give propyl phenyl ketone which further on Clemmenson’s reduction will give butyl benzene
$C_6H_6 + CH_3CH_2CH_2COCl \xrightarrow{AlCl_3}$
$C_6H_5 + COCH_2CH_2CH_3 \xrightarrow{Zn-Hg/HCl} \underset{\text{(Butyl benzene)}}{C_6H_5CH_2CH_2CH_2CH_3}$