diisobutylaluminium hydride in diethyl ether; hexane T=-70 - 20°C;

1: LiHMDS / tetrahydrofuran / 1 h / 20 °C 2: DIBAL-H / diethyl ether; hexane / -70 - 20 °C View Scheme

1.1: 84 percent / K2CO3 / methanol / 3.5 h 2.1: n-butyllithium / hexane; tetrahydrofuran / 1.5 h / -78 °C 2.2: 92 percent / hexane; tetrahydrofuran / -78 - 20 °C View Scheme

potassium carbonate in methanol 3.5 h;