Nucleophilic Substitution Reactions of p-Nitrobenzyl Chloroformate

The reactions of aromatic and aliphatic acyl halides with hydroxylic molecules under solvolytic condition or with low concentrations of reactant in aprotic solvent have been stud-ied extensively.1,2 However, the reaction mechanism is not well established. Bentley and co-workers3,4 have proposed initially that p-substituted benzoyl chlorides react by concurrent addition-elimination and concerted SN2 processes (a loose transition state). Lee5 has proposed that these solvolyses proceed by a combined SN1-SN2 and carbonyl addition pathway. Hudson and Moss6 proposed that the reaction with moderate concen-tration of a hydroxylic species in low polar aprotic solvent favored an addition-elimination mechanism, or a possible mechanism with a tight SN2 transition state