boron tribromide in dichloromethane T=0 - 20°C; 0.75 h;

in hexane; dichloromethane

Multi-step reaction with 3 steps 1: 98 percent / H2 / 5percent Pd/C / tetrahydrofuran; methanol / 5 h / 760 Torr2: 1.) aq. H2SO4, aq. NaNO2, 2.) H2O / 1.) 0 deg C, 0.5 h, 2.) 110 deg C, 0.5 h3: 1.) NaH / 1.) THF, 2.) THF, 60 deg C, 1 h  

Multi-step reaction with 2 steps 1: 1.) aq. H2SO4, aq. NaNO2, 2.) H2O / 1.) 0 deg C, 0.5 h, 2.) 110 deg C, 0.5 h2: 1.) NaH / 1.) THF, 2.) THF, 60 deg C, 1 h