The present invention relates to chiral 1,3-dioxane compounds and diastereomers thereof of the general formula I where R1, R2 and R3 are as defined in the description, and the use of these compounds as chiral dopants for liquid-crystalline systems. The invention further relates to non-polymerizable or polymerizable liquid-crystalline compositions comprising at least one chiral 1,3-dioxane compound of the formula (I) of the invention, the use of these non-polymerizable or polymerizable liquid-crystalline compositions for producing optical components, the use of the polymerizable liquid-crystalline compositions for printing or coating substrates, for preparing dispersions and emulsions, films or pigments and optical components, printed or coated substrates, dispersions and emulsions, films and pigments of this type.