1: 1.) Na2S2O5; 2.) KCN / 1.) H2O, EtOH, 16 h, 55 deg C; 2.) H2O, EtOH, 7 h, reflux 2: LiAlH4 / diethyl ether; tetrahydrofuran / also with BH3; 1.) 16 h, RT; 2.) 1 h, 40 deg C 3: Et3N / CH2Cl2 / 0.5 h / -5 °C View Scheme

1: 1.) Na2S2O5; 2.) KCN / 1.) H2O, EtOH, 16 h, 55 deg C; 2.) H2O, EtOH, 7 h, reflux 2: LiAlH4 / diethyl ether; tetrahydrofuran / also with BH3; 1.) 16 h, RT; 2.) 1 h, 40 deg C 3: Et3N / CH2Cl2 / 0.5 h / -5 °C 4: t-BuOK / 2-methyl-propan-2-ol / 1 h / Ambient temperature 5: sodium bis(2-methoxy-ethoxy)aluminium hydride / toluene / 20 h / Ambient temperature View Scheme