water; hydrogen bromide in acetone T=20°C; Richter cyclization; Cooling with ice; chemoselective reaction;

1: With triethylamine; palladium diacetate in N,N-dimethyl-formamide T=80°C; Solid phase reaction; 12 h; 2: With hydrogen bromide in acetone T=20°C; Solid phase reaction; 1 h;

hydrogen bromide; sodium nitrite T=28°C; 0.25 h;

hydrogen bromide; sodium nitrite 1.) -15 deg C, 10 min; 2.) r.t., 12 min; Yield given. Multistep reaction;