The total synthesis of the nematic liquid crystal material 4-[2-(trans-4'-propylcyclohexyl)ethyl]-1-fluorobenzene through eight steps was reported. In the last step, we used two kinds of reduction methods to transform the carbonyl to methylene and obtained the goal compound. Oneof them was carbonyl reduction by thioacetal hydrogenolysis and the second wasthe Wolff-Kishner-Huangminlong reduction improved from one step to two steps in one pot. Moreover we successfully used the density functional theory (DFT) ab initio quantum chemistry methods to explain the reason of forming the by-product 10, 1-(n-3,6-dioxa-8-hydroxy-octyloxy)-4-[2-(trans-4'-propylcyclo~hexyl)~ethyl]benzene in the process of Wolff-Kishner-Huangminlong reaction. All the calculations in this paper were carriedout by the program of GAUSSIAN 03W.

Key words: nematic liquid crystal material, 4-[2-(trans-4'-propylcyclohexyl)ethyl]-1-fluorobenzene, synthesis, DFT, reduction mechanism for carbonyl to methylene