lithium triethylborohydride in tetrahydrofuran T=-78°C; 5 h;

1: 96.3 percent / tetrahydrofuran / 1.) 10 deg C, 20 min, 2.) room temperature, 30 min 2: 30.9 percent / xylene / 13 h / Heating 3: 80 percent / LiBEt3H / tetrahydrofuran / 5 h / -78 °C View Scheme

1: 30.9 percent / xylene / 13 h / Heating 2: 80 percent / LiBEt3H / tetrahydrofuran / 5 h / -78 °C View Scheme

n-butyllithium in tetrahydrofuran Yield given. Yields of byproduct given;