1: dibenzothiophene With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 2: tri-isopropoxy-borane in tetrahydrofuran; hexane T=20°C; 12 h; 3: With hydrogenchloride in tetrahydrofuran; hexane; water

hydrogenchloride; sec.-butyllithium in neat (no solvent) addn. of s-butyllithium to dibenzothiohene at -78°C under N2 overa few min, addn. of trimethyl borate at this temp., warming to room tem p., cooling in ice bath, addn. of 1 N HCl, extn. with 1 N NaOH, washing with ether, addn. of 3 N HCl; filtration, washing the ppt. with water, diethyl ether;

dihydrogen peroxide in ethanol 2 h; Heating / reflux;

in diethyl ether T=20°C; Inert atmosphereMolecular sieve;

sodium carbonate; tetrakis(triphenylphosphine) palladium(0) in water; toluene T=80°C; 12 h;

sodium carbonate; tetrakis(triphenylphosphine) palladium(0) in ethanol; toluene T=120°C; 12 h;