The Friedel–Crafts alkylations of epoxy enolsilanes with arenes occur under silyl triflate catalysis at low temperatures. Intermolecular alkylations with optically-enriched epoxides occur with conservation of ee. Intramolecular reactions give rise to cyclized products with high diastereoselectivity in good yields. Aziridinyl enolsilanes also undergo selective inter- and intramolecular Friedel–Crafts reactions in a similar manner.