Electronic vs. steric effects in SN2@P reactions

ORGN 515

Marc A. van Bochove, ma.van.bochove@few.vu.nl1, Marcel Swart, marcel.swart@udg.es2, and F. Matthias Bickelhaupt, fm.bickelhaupt@few.vu.nl1. (1) Department of Theoretical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, NL-1081 HV Amsterdam, Netherlands, (2) Institut de Química Computacional, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain
We have shown that the SN2 reaction barrier has a steric origin. Here, we explore how this barrier can be modulated by electronic factors. Thus, raising the steric bulk of the substituents R in SN2@P reactions of Nu– + P(O)R2-L promotes the occurrence of steric pre- and post-barriers that eventually merge into one central barrier. It appears that we can invert this process, while preserving a constantly high steric demand of the substituents, by strengthening the bonding capabilities of nucleophile Nu– and leaving group L– (see figure). Our analyses comprise symmetric (Nu = L) as well as asymmetric SN2@P reactions (Nu ≠ L).

 

Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Organic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007