Highlyenantioselective cross‐aldol reactions between acetaldehyde and activated acyclic ketones are reported for the first time. Various acyclic ketones, such as saturated and unsaturated keto esters, reacted with acetaldehyde in the presence of a chiral primaryamine and a Brønsted acid to afford optically enriched tertiary alcohols in good yields and with excellent enantioselectivities. Trifluoromethyl