1: With 2-nitro-benzenesulfonyl chloride; N-ethyl-N,N-diisopropylamine in acetonitrile T=0 - 65°C; Tiemann Rearrangement; 3 h; Inert atmosphere; 2: With silica gel Tiemann Rearrangement;

ethyl (triphenylphosphoranylidene)acetate T=180°C; 3 h;