Both second-order rate constants of SN2 reactions on benzyl bromide and p-nitrobenzyl bromide with hydroxy nucleophiles and those of the Michael addition reactions of a few amines to p-tolyl vinyl sulfone have been determined. The values of kHOO-/kHO- for benzyl and p-nitrobenzyl bromide were very small, i.e.,1.3and1.2respectively; in the SN2reaction on sp3carbon this may be due to the lack of tight σ-bond formation at the transition state. A very small positive deviation from the Brønsted plots was observed in the Michael addition of hydrazine and other amines top-tolyl vinyl sulfone. This may be due to the small β-value associated with the reaction.