Nonmetallic organic catalysts are provided that facilitate the enantioselective reaction of .alpha.,.beta.-unsaturated ketones. The catalysts are chiral imidazolidinone compounds having the structure of formula (IIA) or (IIB) ##STR00001## or are acid addition salts thereof, wherein, in one preferred embodiment, R.sup.1 is C.sub.1-C.sub.6 alkyl, R.sup.2 is phenyl or 2-methylfuryl, R.sup.3 and R.sup.4 are hydrogen, and R.sup.5 is phenyl optionally substituted with 1 or 2 substituents selected from the group consisting of halo, hydroxyl, and C.sub.1-C.sub.6 alkyl. The chiral imidazolidinones are useful in catalyzing a wide variety of reactions, including cycloaddition reactions, Friedel-Crafts alkylation reactions, and Michael additions.