A student’s first exposure to solving “puzzles” in Organic Chemistry “flies under the radar screen” somewhere around week 7-8 when SN1, SN2, E1 and E2 reactions are introduced. Albeit not apparent at the time, these puzzles are rather simple, and have to do with compounds containing 2° leaving groups, i.e. the ones that can go “either way.” Superior nucleophiles in dipiolar aprotic solvents react via SN2; strong bases in any solvent react via E2 (depending upon which book you read). Superior nucleophiles in polar protic solvents react via SN1 competing with E1. Solving the puzzle of the thing that goes “either way” involves knowing where the other factors in the “stew” push the outcome of the reaction.
