1.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -40 °C 1.2: tetrahydrofuran; hexane / 2.5 h / -40 - 20 °C 2.1: p-toluenesulfonic acid monohydrate / methanol / 12 h / 20 °C 3.1: 91 percent / [Rh(cod)2]BF4; (R,R)-(OMe)2-(PPh2)2-1,1';3',3'';1'',1'''-(naphthyl)4; aq. KOH / tetrahydrofuran / 24 h / 60 °C 4.1: 43 percent / LiAlH4 / diethyl ether / 0.5 h / 0 °C 5.1: 76 percent / TBAF / tetrahydrofuran / 3 h / 20 °C View Scheme