Fastest SN2 Reaction

Correct Answer: C. 1-bromo-3-methylbutane

A quick SN2 reminder: The SN2 reaction is a single-step displacement of a leaving group by a nucleophile. During the transition state, the bond to the nucleophile forms at the same time that the bond to the leaving group breaks. Thus, the nucleophile needs to approach from the back, and configuration at carbon is inverted. The best compound for the reaction, therefore, must be a primary alkyl halide for steric reasons. Assign the carbon centers containing the leaving group as 1°, 2°, 3° (drawing the molecules will assist you in this). C would react faster than A because of less steric hindrance around the carbon center.

Subscribe below to receive the DAT Question of the Day delivered straight to your inbox every morning.