Synthesis of novel 2-trifluoromethyl-1-methylene-3-phenylindene derivatives via carbocyclization reaction of 2-trifluoromethyl-1,1-diphenyl-1,3-enynes

Trifluoromethylated enynyl sulfones 3 were reacted with PhLi at −78 °C for 2–4 h to give 2-trifluoromethyl-1,1-diphenyl-1,3-enynes 6 in good yields. Carbocyclization reaction of 6 with 10 mol% of Pd(OAc)2 in cosolvent of CF3COOH and MC (4:1) at room temperature for 1 h afforded 2-trifluoromethyl-1-methylene-3-phenylindene derivatives 7 in good yields.