1: LiBHEt3; MgCl2 / tetrahydrofuran / 5 h / 0 °C 2: 1.21 g / N-methylmorpholine N-oxide; tetrapropylammonium perruthenate / CH2Cl2 / 3 h / 20 °C View Scheme

1.1: LiBHEt3; MgCl2 / tetrahydrofuran / 5 h / 0 °C 2.1: 1.21 g / N-methylmorpholine N-oxide; tetrapropylammonium perruthenate / CH2Cl2 / 3 h / 20 °C 3.1: n-BuLi / tetrahydrofuran / 0.5 h / -78 °C 3.2: 56 percent / tetrahydrofuran / 4 h / -78 - 0 °C View Scheme

With  lithium triethylborohydride; magnesium chloride in  tetrahydrofuran T=0°C; 5 h;