1.1: TFA; 4 Angstroem molecular sieves / CH2Cl2 / 24 h 1.2: 85 percent / NaHCO3 / CH2Cl2 / 2 h 2.1: 50 percent / benzene / 2 h / Photolysis View Scheme

1: With 4 A molecular sieve; trifluoroacetic acid in dichloromethane 24 h; 2: With sodium hydrogencarbonate in dichloromethane 2 h;