Chiral 1, 3-dioxane compounds

A chiral compound of the general formula I

• or a diastereomer thereof, where
• R1 is [P—Y1—(A1)m—Y2—]qM—Y3—(A2)n—Y4—, and
• R2 and R3 are each, independently of one another and independently of R1, [P—Y1—(A1)m—Y2—]qM—Y3—(A2)n—Y4′—, where
• A1 and A2 are each a spacer having from one to 30 carbon atoms,
• M is a mesogenic group,
• Y1, Y2, Y3 and Y4 are each a chemical single bond, —O—, —S—, —CO—, —CO—O—, —O—CO—, —CO—N(R)—, —(R)N—CO—, —O—CO—O—, —O—CO—N(R)—, —(R)N—CO—O— or —(R)N—CO—N(R)—,
• Y4′ is —O—, —O—CO—, —O—CO—O— or —O—CO—N(R)—,
• R is hydrogen or C1-C4-alkyl,
• P is hydrogen, C1-C12-alkyl, a polymerizable group or a group suitable for polymerization or a radical having a polymerizable group or a group suitable for polymerization,
• m and n are each 0 or 1, and
• q is 1, 2 or 3,
• where A1, A2, Y1, Y2, Y3, Y4, Y4′, M and P and the indices m, n and q of R1 to R3 can be identical or different, and R2 and R3 are attached to the 1,3-dioxane skeleton via the oxygen atom of Y4′, with the proviso that at least one of the radicals Y, in each case adjacent to A, is a chemical bond if one or both of the indices m and n is/are 0.