1: 6-bromohexanoic acid ethyl ester With magnesium; lithium chloride; zinc(II) chloride in tetrahydrofuran T=20°C; 2.5 h; Inert atmosphere; 2: With CuCN*2LiCl in tetrahydrofuran T=-30°C; Inert atmosphere; 3: 4-methyl-benzoyl chloride in tetrahydrofuran T=-30°C; Inert atmosphere;