Mechanistic Source of Regiospecificityin Addition reactions If addition involves a carbocation intermediate and there are two H3C C-H possible ways to add the route producing the Much more stable more alkyl substituted cationic center is lower CH H in energy C、仓,H Alkyl groups stabilize H3C carbocation HMechanistic Source of Regiospecificityin Addition Reactions If addition involves a carbocation intermediate – and there are two possible ways to add – the route producing the more alkyl substituted cationic center is lower in energy – alkyl groups stabilize carbocation