Figure 2

Synthesis of compounds 1, 2, and 3. (a) Phenylacetylene (5), Pd(PPh₃)₂Cl₂, CuI, (Et)₃ N, 50°C, 1 h, 92.5%. (b) Tetraphenylcyclopentadienone (7), diphenyl ether, reflux, 48 h, 78.6% for 8, 72.6% for 16. (c) N-Bromosuccinimide (NBS), 2,2′-azobis(2-methylpropionitrile) (AIBN), CCl₄, reflux, 4 h, 75.8% for 9, 78.0% for 17. (d) P(OEt)₃, reflux, 24 h, 74.0% for 10, 82.0% for 18. (e) PPh₃, DMF, reflux, 24 h, 64.0%. (f) 4-(Diphenylamino)benzaldehyde (12), NaH, THF, rt, 36 h, 40.0%. (g) 4-(Dimethylamino)benzaldehyde (13), NaOt-Bu, MeOH, reflux, 24 h, 36.0%. (h) 1-ethynyl-4-methylbenzene (14), Pd(PPh₃)Cl₂, CuI, Et₃N, 50°C, 1 h, 92.3%.