(a) Correlation of enolate nucleophilicities N with pKa of the corresponding
CH acids 1, 1′, 2a,
and 3a. (b) The Brønsted plot shows a linear relationship
between
the enolate reactivities (lg k2) toward 6c and the acidity constants pKa of the corresponding CH acids 1, 1′, 2a, and 3a.