Title 40. NUCLEOPHILIC AROMATIC SUBSTITUTION.pdf ✅

PHARMD GURU Page 1 NUCLEOPHILIC AROMATIC SUBSTITUTION:  Nucleophilic aromatic substitution is a nucleophilic substitution reaction in which a nucleophile displaces a leaving group bonded to the carbon ring of an aromatic compound.  In this reaction, a nucleophile attacks an aromatic ring that is deficient in electrons.  The presence of an electron-withdrawing group facilitates the reaction.  A typical leaving group is a halide, like fluoride or chloride. CONDITIONS FOR NUCLEOPHILIC AROMATIC SUBSTITUTION: Here are the facts and conditions for nucleophilic aromatic substitution reaction.  The attacking species must be a strong nucleophile, i.e., it must have electrons that can bond with the carbon atom of the ring.  The aromatic ring is poor in electrons, i.e., electron-deficient. The presence of an electron-withdrawing group activates the ring and makes it electron deficient.  The leaving group is usually a nucleophilic species like a halide (X– ) attached to a carbon atom.  The nucleophile attacks at a site determined by the leaving group’s position, not by steric and electronic factors. EXAMPLES: Here is an example of nucleophilic aromatic substitution: 1-chloro-4-nitrobenzene (Cl-(C6H4)-NO2) reacts with sodium methoxide (CH3ONa) to produce 1-methoxy-4-nitrobenzene (CH3O-(C6H4)-NO2). Cl-(C6H4)-NO2 + CH3ONa CH3O-(C6H4)-NO2 + NaCl NUCLEOPHILIC AROMATIC SUBSTITUTION