Nucleophilic Substitution at Unactivated Vinylic Carbon. Factors Conducive to the Energetic Preference for the In-plane SN2 pathway

초록

The gas-phase nucleophilic bimolecular substitutions at unactivated vinylic carbon (CH2=CHCl, 1) by four nucleophilis (OH-, SH-, Cl- and Br-) are investigated theoretically at the G2(+) (MP2) level. The results show that the stronger nucleophiles (OH- and SH-) substitute by an out-of-plane SN2 path with retention (SNpi) but an in-plane SN2 path (SNsigma) with inversion of configuration is preferred for the substitution by the weaker bases, Cl- and Br-.