1: (4-methylphenyl)methyltetrahydrothiophenium tetrafluoroborate With lithium hexamethyldisilazane in tetrahydrofuran T=-78°C; 2 h; 2: diethyl(phenyl)borane in tetrahydrofuran T=-110 - 0°C; 3: With sodium hydroxide; dihydrogen peroxide in tetrahydrofuran T=20°C; 8 h; Further stages.;