1.1: methanol / 6 h / 20 °C / Inert atmosphere 2.1: sodium tetrahydroborate / methanol / 12 h / Inert atmosphere 3.1: sodium hydride / tetrahydrofuran / 0.5 h / 0 °C / Inert atmosphere 3.2: 12 h / Inert atmosphere; Reflux 4.1: Grubb's 2nd generation catalyst / toluene / 12 h / 40 °C / Inert atmosphere 5.1: Pearlman's catalist; hydrogen / methanol / 12 h / 20 °C / Inert atmosphere View Scheme