1H-imidazole; 4-(N,N-dimethlyamino)pyridine in N,N-dimethyl-formamide T=0°C; 10 h;

acetic anhydride; pyridinium chlorochromate in dichloromethane T=20°C; 1 h; Molecular sieve;

AuNTf2(SPhos); water in methanol T=20°C; Inert atmosphere;

1: 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione / ethyl acetate / Reflux 2: diethyl ether / 1 h / 0 °C 3: acetic anhydride; pyridinium chlorochromate / dichloromethane / 1 h / 20 °C / Molecular sieve View Scheme

1: CH3CBr2CO2Et With tert.-butyl lithium in tetrahydrofuran T=-78 - 0°C; 3.5 h; 2: 1-O-TBDPS-propan-2-one in tetrahydrofuran T=20°C; 0.5 h; 3: With hydrogenchloride in ethanol 3 h; Heating; Further stages.;