Liquid-crystalline medium and liquid-crystal display

A liquid-crystalline medium of positive dielectric anisotropy based on a mixture of compounds, comprising one or more compounds of formula I

• in which
• R1 and R2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF3, or at least monosubstituted by halogen, in which, one or more CH2 groups may be replaced by —O—, —S—, —C≡C—, —CH═CH—, —(CO)O— or —O(CO)— in such a way that O atoms are not linked directly to one another, and
• one or more compounds of formulae K-1 to K-11:
• in which
• R0 denotes n-alkyl, oxaalkyl, fluoroalkyl or alkenyl, each having up to 9 C atoms.