Development of fluorinated ferroelectric liquid crystals through an enzymatic reaction.

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Ferroelectric liquid crystals (FLC) are known to be important high-speed switching devices, and their response time strongly depends on the magnitude of spontaneous polarization. A recent study revealed that chiral FLC compounds which involve optically active 1,1,1-trifluoro-2-alkanols possess remarkable characteristics of a wide temperature range of Sc^<**> phase, a large spontaneous polarization, and a short responsetime. Becausethe target compounds are FLC compounds, large scale preparation is particularly desired. Candida antarctica-lipase (CAL) -catalyzed esterification in hexane using vinyl acetate as acyl donor was successfully utilized for optical resolution of racemic 1,1,1-trifluoro-2-alkanols to provide corresponding (S) -acetates in an optically pure state. Five types of optically pure alkanols, i.e.1,1,1-trifluoro-2-octanol, 1,1,1-trifluoro-2-nonanol, 1,1,1-trifluoro-2-decanol, 1,1,1-trifluoro-2-undecanol, and 1,1,1-trifluoro-8-benzylo-2-octanol, were thus obtained by the … More CAL-catalyzed acylation.Antiferroelectric liquid crystal (AFLCs) compounds, which possess a chiral bis (trifluoromethyl) alkanediol moiety, are also known to be important high-speed switching devices. Enantioselective hydrolysis of diacetates of bis (trifluoromethyl) alkanediols has been demonstrated. CAL was chosen from among commercial enzymes as the one most able to enantioselectively hydrolyze the acetyl group of diacetates giving five types of optically pure diols and diacetates. Among compounds obtained by CAL-catalyzed reaction, 1,4-bis (1,1,1-trifluoro-2-dodecanyl) benzene has been successfuly converted to a new AFLCs compound.The lipase-catalyzed reaction can be used in a large scale preparation, the present method therefore affords a valuable method of preparing optically pure 1,1,1-trifluoro-2-alkanols and bis (trifluoromethyl) alkanediols. Key compounds for making ferroelectric and antiferroelectric liquid crystals were thus developed via an enzymaticreaction as a key reaction. Less