1: C12H21BrO2 With 1,1-dimethylethylmagnesium chloride in tetrahydrofuran T=-78°C; 0.166667 h; Inert atmosphere; 2: n-hexylMgCl With 1-methyl-pyrrolidin-2-one; buta-1,3-diene; nickel dichloride in tetrahydrofuran T=0°C; 1 h; Inert atmosphere;