2-bromobenzene boronic acid in dichloromethane T=25°C; 48 h;

1: acryloyl chloride With 1-butyl-5-hydroxymethyl-3-methyl-3H-imidazol-1-ium NTf2; triethylamine; 3-butyl-5-hydroxymethyl-1-methyl-3H-imidazol-1-ium triflimide in dichloromethane T=-20°C; 0.5 h; 2: 2,3-dimethyl-buta-1,3-diene With hydroquinone T=120°C; Diels-Alder reaction; 12 h; 3: With lithium hydroxide in methanol; water 12 h;

Multistep reaction;

2-(N,N-dimethylamino)-pyridine; palladium (II) trifluoroacetate; oxygen; toluene-4-sulfonic acid in 1,3,5-trimethyl-benzene T=100°C; P=760.051 Torr; 24 h;

oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane T=0°C; Inert atmosphere;