sodium hydride Yield given. Multistep reaction;

1: 1.) sodium hexamethyldisilazide, 2.) HMPA / 1.) THF, - 78 deg C, 2.) THF, - 65 deg C 2: 92 percent / lithium triethylborohydride / tetrahydrofuran / 1.) - 78 deg C, 30 min, 2.) - 78 deg C - room temperature, 30 min, 3.) room temperature, 15 min View Scheme