magnesium silicate; 4 A molecular sieve; sodium acetate; Celite; pyridinium chlorochromate in dichloromethane T=20°C; 1 h;

ozone in dichloromethane T=-78°C;

1: 52 percent / 4-(dimethylamino)pyridine; pyridine / CH2Cl2 / 4 h / 20 °C 2: 95 percent / molecular sieves 4 Angstroem; florisil; sodium acetate / Celite; pyridinium chlorochromate / CH2Cl2 / 1 h / 20 °C View Scheme

potassium tert-butylate; triphenylphosphine in toluene T=-20°C;