Write three methods by which alkyl side chains can be introduced into the benzene ring.

Explanation

The methods by which alkyl side chain can be introduced into the benzene ring are-
by using (a) `CH_3CH_2X,AlCl_3,` (b) `CH_2,HF` and c `CH_3CH_2OH,BF_3` or concentrated `H_2SO_4` in Friedel-Crafts alkylation reaction .
by acylation of benzene using `CH_3COCl or (CH_3CO)_2O ,AlCl_3` followed by clemmensen reduction
of the formed ketone.
by reacting `CH_3CH_2Br ` with `Ph_2CuLi` according to Corey -House synthesis.