1: sodium cyanoborohydride / methanol / 1 h / 20 °C / pH Ca. 3 2: 1,8-diazabicyclo[5.4.0]undec-7-ene / tetrahydrofuran; N,N-dimethyl-formamide / 2 h / |Reflux 3: water / benzene / 120 °C 4: zinc; acetic acid / water / 5 h / 20 °C 5: boron trichloride / dichloromethane / -10 - 20 °C View Scheme

Multi-step reaction with 2 steps 1: sodium cyanoborohydride / methanol / 1 h / 20 °C / pH Ca. 32: 1,8-diazabicyclo[5.4.0]undec-7-ene / tetrahydrofuran; N,N-dimethyl-formamide / 2 h / |Reflux  

With  hydrogenchloride; sodium cyanoborohydride in  methanol; water 0.5 h;  Inert atmosphere;   

Multi-step reaction with 3 steps 1: acetic acid / 4 h / 100 °C2: tin(ll) chloride / ethyl acetate / 10 h / 20 °C3: hydrogen / ethyl acetate / 5 h / 760.05 Torr