Nulceophilic Displacements at Carbonyl Compounds

Abstract

The nucleophilic displacements at carbonyl center are remarkable. Mainly stepwise mechanism was found in these reactions. The stepwise mechanism with rate-limiting addition of the nucleophilie to the carbonyl group to form zwitterionic tetrahedral intermediate was a common type of mechanism. Such as, Dey et al. [1] proposed the pyridinolyses of α-chloroacetanilides proceed via a stepwise mechanism with rate-limiting addition of the nucleophile to the carbonyl group to form zwitterionic tetrahedral intermediate (T ±). In some cases concerted mechanism was found. Oh and coworkers [9] reported that a concerted mechanism with a hydrogen bonded cyclic transition state for the aminolysis of aryl N-allyl thiocarbamates with benzylamines in acetonitrile The mechanism change from stepwise to concerted was also found in some cases. It was concluded that the change of the amine from benzylamines to anilines causes a shift of the aminolysis mechanism from a concerted to a stepwise process. This paper includes an exclusive review of literature from 1997 to 2015.