Theoretical Studies on the Acid-Catalyzed Hydrolysis of Sulfinamide

摘要

Ab initio calculations were carried out on the gas phase acid-catalyzed hydrolysis reactions of sulfinamide using the 3-21G* basis sets. Single point calculations were also performed at the MP2/6-31G* level. The first step in the acid-catalyzed hydrolysis of N-methylmethanesulfinamide, グ, involves protonation. The most favorable form is the O-protonated one, ケ, which is then transformed into a sulfurane intermediate, ゲ, by addition of a water molecule. The reaction proceeds further by an intramolecular proton transfer from O to N (TS2), which is followed by N-S bond cleavage (TS3) leading to the final products. The rate determining step is the N-S bond cleavage (TS3) at the RHF/3-21G* level, whereas it becomes indeterminable at the MP2/6-31G*//3-21G* level of theory. However, the substituent effect studies with N-protonated N-arylmethanesulfinamide, スゲ, at the MP2/6-31G*//3-21G* level support the N-S bond breaking step as rate limiting.