| abstract |
An optically active substance having a δ-valerolactone ring is described which is represented by the formula (1):n wherein X is -O-, -OCH₂- or -SCH₂-, R₁ is C1 - 18 alkyl, n is an integer of from 1 to 14, m is 1 or 0, Y is a direct bond, -OCO-, -CO₂-, -CH₂O or -OCH₂-, Z is -O-, -CO₂- or -CH₂O, A₁ and A₂ are H, F, Cℓ or cyano, and the carbon atom marked with "*" indicates the asymmetric carbon atom. This optically active substance is used alone or as a mixture thereof with other optically active substances. |