Abstract Chiral (salen) Mn (III) Cl complexes catalyze epoxidation of cyclic 1, 3-dienes with moderate-to-good enantioselectivity. A new catalyst (2), bearing sterically hindered and electron donating OSi (iPr) 3 (OTIPS) substituents, induces up to 12% higher selectivity than the previously-reported tert-butyl substituted analog 1.