sodium hydroxide; phenylmethyltriethylammonium bromide in water; toluene T=20°C; 20 h;

in tetrahydrofuran; hexane T=-78 - 20°C;

1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.833333 h; 2: With sulfur dioxide in tetrahydrofuran; hexane T=-78°C; 1 h; 3: With N-chloro-succinimide in dichloromethane T=20°C;