9,9-dimethyl-4,6-bis(diphenylphosphino)xanthene; tetrabutyl-ammonium chloride; caesium carbonate; tris(dibenzylideneacetone)dipalladium (0) in toluene T=80°C; 1 h;

tetrabutyl-ammonium chloride; caesium carbonate; 9,9-dimethyl-4,5-bis(diphenyl-phosphino)xanthene; tris(dibenzylideneacetone)dipalladium (0) in toluene T=120°C; 2 h;

MeCu(SePh)Li in tetrahydrofuran T=0°C; Elimination; aromatization; 2.5 h;

sodium tetrahydroborate; nickel dichloride in tetrahydrofuran; methanol T=0°C; Reduction; 0.25 h;

chlorine dioxide in ethyl acetate T=20°C; 3 h;

1: 1-bromo-3-methyl-benzene With tert.-butyl lithium in n-heptane; anhydrous butyl ether T=-10 - 20°C; Inert atmosphereSchlenk technique; 2: With DABCO-bis(sulfur dioxide) in 1,4-dioxane; n-heptane; anhydrous butyl ether T=20°C; 2 h; Inert atmosphereSchlenk technique; 3: p-trifluoromethanesulfonyloxytoluene With potassium phosphate; palladium diacetate; (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(bis(3,5-bis(trifluoromethyl)phenyl)phosphine) in 1,4-dioxane; n-heptane; anhydrous butyl ether T=110°C; 16 h; Inert atmosphereSchlenk techniqueSealed tube;

aluminium trichloride in dichloromethane T=25°C; Rate constantProduct distribution;

1: 81 percent / 12 h / 60 - 65 °C 2: 78 percent / MeCu(SePh)Li / tetrahydrofuran / 2.5 h / 0 °C View Scheme

iron(III) chloride T=110°C; 0.166667 h; microwave irradiation; Title compound not separated from byproducts.;

trifluoromethylsulfonic anhydride in tetrachloroethane, 1,1,2,2- T=120°C; 12 h; Title compound not separated from byproducts.;