Question

Reactivity of $MeMgBr$ with the following in the decreasing order is:

• A. (i) > (ii) > (iii) > (iv)
• B. (iv) > (i) > (ii) > (iii)
• C. (i) > (iii) > (ii) > (iv)
• D. (iv) > (ii) > (iii) > (i)

Answer 1

Answer: (B)

The order of reactivity of G.R. with different functional groups is aliphatic aldehyde $>$ aromatic $>$ aldehyde $>$ aliphatic ketone $>$ aromatic ketone. Also, EWG favours NA reaction
iv. is aliphatic ketone with $-I$ effect of $Ph$ group.

$(+R$ effect is not possible since the double bond of benzene ring is not in conjugation with ( $C=O)$ group. So, (iv) is the most reactive ketone
Hence, the order is $iv>i>ii>iii$