These spectra were recorded by and discussed with Mr. H . Hienisrru and Mr. W . A . Mellink. Mass spectra were obtained on a AEI MS-902 by Mr. A . Kiewiet. Optical rotations were measured on a Perkin Elmer 241 Polarimeter. The O R D and C D spectra were recorded on a Cary 60 recording spectropolarimeter equipped with a Cary 6002 C D accessory.
4-(9-Fluoreylidene) -I ,2,3.4-tetrahydrophenunthrene ( 5 )a. The coupling of 9-fluorenone (4) and 2,3-dihydro-4(1H)phenanthrone (3) was performed following the general procedure described for the coupling of 3'. A mixture of 3 (2.05 g, 10.5 mmol) and 4 (1.89 g, 10.5 mmol) in 25 ml of T H F was added to the slurry of the Ti(ll) species. After a work-up as described previously 3.5 g of a yellow oil was obtained. Chromatography over alumina (petroleum ether 40/60 as eluent) yielded an apolar product mixture, which could be separated via preparative TLC (AI,O,, not-activated, n-hexane) in 9,9'-bifluorenyl (6) (0.20 g. 0.66 mmol, 13",,. m.p. 248-249°C. lit.:" m.p. 247°C) cross coupled olefin 5 (0.12 g, 0.34 mmol, 3.2 %) and 1 + 2 (0.38 g, 1.04 mmol, 19 7,).b. The coupling was performed as described above, using a mixture of 3 (0.78 g, 4.0 mmol) and 4 (3.06 g. 17.0 mmol) in 25 ml of THF. After work-up as described previously. 3.4 g of a red semisolid was obtained. Column chromatography (Al,O,, petroleum ether 40/60) followed by preparative TLC (of the apolar fraction of the first separation) yielded bifluorenylidene, 7 ( I . I4 g, 2.0 mmol, 35%, and 5 (0.34 g, 0.9 mmol, 25 %). Crystallization of 5 from n-hexane, yellow needles, m.p. 236-238°C. UV (n-hexane): A , , , 355 nm (1.54 x lo4), 262 (4.15 x 10,) 218 (15.0 x lo4, sh).
