摘要:
A new synthesis of 1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane (2) is reported. Easy preparation of gram quantities of 2 is accomplished by treatment of alpha,alpha'-dibromo-alpha,alpha,alpha',alpha'-tetrafluoroxylene with a complex low-valent form of Ti which is made by reduction of TiCl4 with equimolar quantities of LiAlH4 in THF. Use of high-dilution techniques is required for the reaction to be successful. The formation of 2 is believed to proceed via the reactive monomeric species alpha,alpha,alpha',alpha'-tetrafluoro-p-xylylene (4).