1: N-ethyl-N,N-diisopropylamine / dichloromethane / 0.75 h / 0 - 20 °C 2: tetrabutyl ammonium fluoride / tetrahydrofuran / 0.5 h / 20 °C 3: sodium hydride / tetrahydrofuran / 24 h / 0 - 20 °C 4: palladium 10 on activated carbon; hydrogen / methanol / 50 °C View Scheme