1: 1,3-benzoxazole; carbon dioxide With [Cu(N,N′-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene)Cl]; potassium tert-butylate in tetrahydrofuran T=80°C; P=760.051 Torr; 14 h; Inert atmosphere; 2: ethyl iodide in N,N-dimethyl-formamide T=80°C; 5 h; Inert atmosphere;

1: 2N NaOH / methanol / 2 h / Ambient temperature 2: (COCl)2 / CH2Cl2 / 3 h / Ambient temperature View Scheme