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

1.1: 78 percent / K2CO3 / dimethylformamide / 24 h / 20 °C 2.1: TFA; 4 Angstroem molecular sieves / CH2Cl2 / 24 h 2.2: 85 percent / NaHCO3 / CH2Cl2 / 2 h View Scheme

in benzene 2 h; Photolysis;