lithium triethylborohydride in tetrahydrofuran T=20°C; 2 h;

lithium aluminium tetrahydride in diethyl ether 2 h; Heating;

1.1: LDA / tetrahydrofuran / 0.75 h / -78 °C 1.2: tetrahydrofuran / 3 h / -78 °C 1.3: 78 percent / tetrahydrofuran / -78 °C 2.1: 88 percent / LiHBEt3 / tetrahydrofuran / 2 h / 20 °C View Scheme

1: 83 percent / TBAF / tetrahydrofuran 2: 88 percent / LiHBEt3 / tetrahydrofuran / 2 h / 20 °C View Scheme