in tetrahydrofuran; N,N-dimethyl-formamide

With  boron trichloride in  hexane; pentane  1.) 0 deg C, 15 min, 2.) RT, 2 h;   

Multi-step reaction with 2 steps 1: 1) NaH / 1) THF, 2) room temperature, 1 h2: 60 percent / BCl3 / pentane; hexane / 1 h / Ambient temperature