Optically active fluorine-containing

Extensive research has already been carried out on incorporation of fluorine into molecules which can lead to profound and unexpected results on biological activities and/or physical properties [ 1 - 5]. In particular, optically active fluorine-containing molecules have been recognized as a relatively important class of materials because of their interesting characteristics and potential applicability to optical devices such as ferroelectric or antiferroelectric liquid crystals [6-11]. Recent investigations in this field have opened up the possibility for the... 

Optically active fluorine-containing alcohols (91-93% ee) (entries 12 and 13) and deuterio alcohols (84-94% ee) (entries 14 and 15) are synthesized, respectively, by the enantioselective alkylation of fluorine-containing aldehyde and deuterio aldehyde using DBNE. 

Use of Optically Active Fluorine-containing Molecules. Ethyl a, 3-dihydroxy-y,y,y-trifluorobutyrates, potent building blocks for the synthesis of CF3 analogs of 6-deoxysugars, were prepared in a syn or anti selective fashion (41) To construct the carbon framework of these molecules effectively, two different pathways were employed. 

Preparation of optically active fluorine-containing y-lactones with four chiral centers 05Y26. 

Koimo T, Tanikawa M, Ishihara T, Yamanaka H. Palladium-catalyzed coupling reaction of fluoroalkylated propargyl mesylates with organozinc reagents novel synthesis of optically active fluorine-containing trisubstituted aliens. Chem. Lett. 2000 1360 1361. 

As the demand for optically active fluorinated compounds increases, the importance of the development of asymmetric synthetic methods for fluorinated building blocks grows. On the other hand, sulfur functionalities such as phenylthio and dithianyl groups have been used as useful reactive units for a variety of chemical transformations. Therefore, various trifluoromethyl ketones containing a sulfur functionality have been reduced with various microorganisms l182-185 . 

Asymmetric transformation of fluorine-containing ketones or esters into the corresponding optically active alcohols or acids by enzymes along with the discussion on the effect of fluorinated alkyl groups during the enzymatic optical resolution or diastereoselective reactions is described. 

The fluorine-containing polymers for materials with complete internal light-reflection are reviewed. The general kinetic control features for the synthesis of block polymerisation fluoroalkylmethacrylates (FMA), their copolymerisation with different vinyl monomers, their relative activity and the polymerisation of FMA in presence of nitroxyl radicals are discussed. The basic properties of the more frequently used FMA for materials with complete internal light-reflection, are characterised. The new optical transparent fluorine polymers, also containing per-fluorinated cyclobutane and aromatic fragments are reviewed. Data from the literature and original results are presented. 

Requirements for the FLC moiety are as follows (i) the LC group includes a chiral center to exhibit an optical activity (ii) the LC group or molecule has a smectic phase with a non-zero tilt angle, that is, a chiral smectic C phase and (iii) the LC group has a non-zero dipole moment that is perpendicular to a molecular long axis. According to these requirements, three types of polythienylene derivatives containing the fluorinated asymmetric moiety in the LC side-chains were synthesized. The polymer structures are shown in Scheme 12.4. 

The data collated in Table 8 allow a valid comparison of the relative effects of either a fluorine or a chlorine atom attached directly to the optically active center of the chiral dopant [69]. The transition temperatures and Pg of the mixture containing the... 

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