Question

Reactivity of `MeMgBr` with the following in the decreasing order is :
(i)
A. `(i) gt (ii) gt (iii) gt (iv)`
B. `(iv) gt (i) gt (ii) gt (iii)`
C. `(i) gt (iii) gt (ii) gt (iv)`
D. `(iv) gt (ii) gt (iii) gt (i)`

Answer 1

Correct Answer - B
(b) The order of reactivity of `G.R` with different functional groups is aliphatic aldehyde gt aromatic aldehyde gt aliphatic ketone gt 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 gt i gt ii gt iii`.