Probing reaction mechanisms of additions to alkenes via correlations

ORGN 27

Donna J. Nelson1, Ruibo Li2, and Christopher N. Brammer2. (1) Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, (2) Department of Chemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
Application of our correlation method to selecting among proposed mechanisms will be demonstrated. This method involves generating a plot of log relative rate values versus alkene IPs for each reaction; in this plot, the steric requirements of the alkene must be designated. Each plot reveals (1) whether the corresponding reaction is electrophilic or nucleophilic and (2) whether there are significant steric effects in the reaction. In some reactions, no correlation in the plot is obvious until the alkenes are labeled according to steric requirements. Some reactions of alkenes to which this technique has been applied successfully are hydroboration, oxymercuration, bromination, oxidation by using palladium chloride, and hydrogenation with Wilkinson's catalyst.