Optically active ether derivatives, preparation process therefor, liquid crystal materials and an optical switching element

摘要

Disclosed are herein optically active ether derivatives represented by the formula (I): ##STR1## (wherein X represents --COO-- or --OCO--; A represents an alkyl or alkoxyl group having 3 to 15 carbon atoms; R represents an alkyl or alkyloxyalkyl group having 1 to 20 carbon atoms; l and m each represents a number of 1 to 2; and * indicates an asymmetric carbon atom), preparation processes therefor, liquid crystal materials containing such ether derivatives as active ingredient, and an optical switching element using said liquid crystal materials as liquid crystal element.