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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3g3107

In which of the following reactions is dichlorocarbene the species that attacks the organic substrate?

APhenol with $CHCl X_{3}$ and aqueous $NaOH$ , giving salicylaldehyde
BAniline with $CHCl X_{3}$ and alcoholic $KOH$ , giving phenyl isocyanide
CPyrrole with $CHCl X_{3}$ and $NaOEt$ , giving 3-chloropyridine
DBenzene with $CHCl X_{3}$ and anhydrous $AlCl X_{3}$ , giving triphenylmethane

Answer: A, B, C

The first three use a strong base, which removes the proton of

CHCl X_{3}

and then expels chloride to give

: CCl X_{2}

, which attacks the phenoxide ring, the amine nitrogen and the pyrrole C=C respectively. With

AlCl X_{3}

(a Lewis acid, no base) the electrophile is a

CHCl X_{2} X^{+}

-type species in a Friedel-Crafts reaction, not a carbene.

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