sodium cyanoborohydride in acetic acid T=10 - 25°C; Inert atmosphere; regioselective reaction;

1: sodium cyanoborohydride / acetic acid / 10 - 25 °C / Inert atmosphere 2: N-ethyl-N,N-diisopropylamine / dichloromethane / 1 h / -78 °C / Inert atmosphere 3: 1,3-bis-(diphenylphosphino)propane; palladium diacetate / N,N-dimethyl-formamide / 24 h / 60 °C / Inert atmosphere View Scheme