Quantum mechanical calculations (B3LYP/6-31G(d)) were used to study the substituent effects and the concertedness of the alkenyl migration/electrophilic aromatic substitution reactions recently reported by Oshima and co-workers. Our calculations suggest that these systems prefer stepwise mechanisms with their aryl attack steps having the highest energy transition structures, but that in some highly substituted cases, effectively concerted but very asynchronous processes may occur.