1: CpMgCl; dodecyl bromide in tetrahydrofuran T=60°C; 6 h; Inert atmosphere; 2: With n-butyllithium in hexanes; diethyl ether T=20°C; 0.666667 h; Inert atmosphere; 3: zirconium tetrachloride in hexanes; diethyl ether T=20°C; 3 h; Inert atmosphere;