# Effect of trifluoromethyl substituent on electrophilic substitution [duplicate]

Problem -

Find which carbon is most susceptible to electrophilic attack (among carbons numbered $$1$$ to $$6$$):

Answer given (may not be the correct one) -

$$2$$

### My question -

$$1.$$ I know that $$\ce{-CCl3}$$ group exerts a negative hyperconjugation effect, hence acting as a deactivating and meta-directing group. If $$\ce{-CF3}$$ has a similar effect (which dominates over $$\mathrm{-I}$$ effect), then in that case phenyl ring D will be more electron-rich as compared to ring B - since the ring B, being attached at para of the main ring A, will participate in resonance due to the negative hyperconjugation of $$\ce{-CF3}$$ group. Since resonance does not result in a positive charge at the meta carbon of ring A, so I feel ring C should be more susceptible to electrophile. Within ring C, I expect only inductive effect to operate, so the carbon farthest from ring A will be richest in electrons. Accordingly my answer in this case will be $$5$$.

$$2.$$ If $$\ce{-CF3}$$ does not exert negative hyperconjugation - then in that case, only inductive effect will decide the electron density and consequently the carbon farthest from $$\ce{-CF3}$$ group will be most electron-rich. My answer in this case will be $$6$$.

In either case, I don't see how $$2$$ can be the answer. Is the answer key wrong? If yes, then which of my two reasonings is correct? If no, then what am I missing?

• @Ashish Ahuja - it does, it's the same question from the same test paper!
– TRC
Jul 22 '21 at 6:34
• If you don't mind, can you tell me whether, the paper mentioned is for mains or adv? Jul 22 '21 at 9:21
• @Rishi Advanced - and their answer key to this one was wrong btw, the correct answer is 4.
– TRC
Jul 22 '21 at 13:31