Spiro[3.4]oct-1-ene,2-[2,2,3,3,5,5,6,6,7,7,8,8-dodecafluoro-1-(trifluoromethyl)spiro[3.4]oct-1-yl]-1,3,5,5,6,6,7,7,8,8-decafluoro-3-(trifluoromethyl)-