Liquid-crystalline medium and liquid-crystal display comprising the same

A liquid-crystalline medium comprising one or more compounds of formula S

• in which
• denotes
• denotes, in each occurrence independently of each other,
• n denotes 1 or 2,
• RS denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy preferably having 1 to 7 C atoms, wherein one —CH2— group may be replaced by cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, or 1,3-cyclopentenylene, preferably by cyclopropylene or 1,3-cyclopentylene, or denotes alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, wherein one —CH2— group may be replaced by cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, or 1,3-cyclo-pentenylene, preferably by cyclopropylene or 1,3-cyclopentylene, and
• XS denotes F, Cl, CN, NCS, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, the latter four groups preferably having 1 to 4 C atoms, preferably F, CF3 or OCF3.