1-ARYL-F-1,3-BUTADIENES AND UNSYMMETRICAL ALPHA,OMEGA-DIARYL-F-POLYENES

Para-substituted 1-aryl-F-1,3-butadiene derivatives p-R-C6H4-CF=CFCF=C F2 (2a-g) where R = H, CH3, OCH3, OC6H11, N(CH3)(2), Br, and CF3, have been prepared by reaction of appropriate arylmagnesium bromides with F-1,3-butadiene. F-19 NMR chemical shies correlate with a, Hammett sub stituent constants. Compounds 2a-e react on their terminal perfluorovi nyl group with C-nucleophiles and were used as intermediates in subseq uent reactions with suitable organolithium compounds for the synthesis of a new series of unsymmetrically substituted alpha,omega-diaryl-F-p olyenes RC6H4(CF=CF)(n)C6H4R', where n = 2 or 3 and R' is one of the s ubstituents specified above. A variety of new synthons containing alph a,omega-diaryl-F-1, 3-butadiene skeleton and reactive Br, OH, CH=O, an d COOH functionalities in para-positions on aromatic rings has been al so prepared. Structural aspects, NMR spectra, and mesogenic properties of the title compounds are discussed.