Protonation study of some enamine systems

The properties of enamines depend on slight changes in reaction conditions or structural factors. From the analysis of the data which is available in the literature, B3LYP/6-311 +G(3df,3pd)//MP2/6-31+G** calculations and usin g the Taft and Topsom model of the intrinsic substituent effect in the basi city, we found a resonance effect that explains why vinylamine and N,N-dime thylvinylamine are both carbon and not nitrogen bases (the resonance factor for vinylamine increases carbon basicity by about 56 kcal/mol). (C) 2001 E lsevier Science B.V. All rights reserved.