1: 1.)disiamylborane, 2.) HOAc / 1.) THF, -40 deg C, 2 h , - 20 deg C, 4 h, 0 deg C, 1 h, 2.) 25 deg C, 4 h 2: 1.) t-BuLi, 2.) CuI*Me2s / ether/THF 3: 100 percent / LiOH / tetrahydrofuran; H2O / 14 h / 25 °C View Scheme

bis-(1,2-dimethylpropyl)borane; acetic acid 1.) THF, -40 deg C, 2 h , - 20 deg C, 4 h, 0 deg C, 1 h, 2.) 25 deg C, 4 h; Yield given. Multistep reaction;