An optically active 2-cyano-2-methyl-alkanoic acid represented by the formula: ##STR1## is produced by optical resolution of the corresponding racemic mixture thereof with an optically active amine and is reduced to provide an optically active 2-cyano-2-methyl-1-alkanol represented by the formula: ##STR2## wherein R.sub.1 denotes an alkyl groups having 3-10 carbon atoms, R.sub.2 denotes an alkyl group having 2-10 carbon atoms and C* denotes an asymmetric carbon atom. These compounds are characterized by having a CN group with a large dipole moment directly attached to an asymmetric carbon atom and are effective for controlling the liquid crystal state of a liquid crystal composition when added thereto.
通过对相应的外消旋混合物进行光学分辨,与光学活性胺反应,制备出由以下式表示的光学活性2-
氰基-2-甲基-酸:##STR1## 并还原得到由以下式表示的光学活性2-
氰基-2-甲基-1-醇:##STR2## 其中,R1表示具有3-10个碳原子的烷基基团,R2表示具有2-10个碳原子的烷基基团,C*表示一个不对称碳原子。这些化合物的特点是具有一个大的偶极矩CN基团直接连接到一个不对称碳原子,并且在添加到液晶组合物中时有效地控制液晶态。