1: 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl-4',4',5',5'-tetramethyl-1,3,2-dioxaborolane With [(diglyme)NiBr2]; 2-methyl-propan-1-ol; potassium tert-butylate; Ru(4,4′,4''-tri-t-butyl-2,2′;6,2″-terpyridine)Cl3 in di-isopropyl ether 0.0833333 h; Inert atmosphereCooling with ice; 2: 4-bromo-tetrahydro-2H-pyran in di-isopropyl ether T=60°C; 24 h; Inert atmosphere;