1: 73 percent / DIBAL / toluene / 5 h / -78 °C 2: 1.) NaH, 2.) n-Bu4NHSO4 / 1.) THF, 2.) THF, RT, 10 h 3: 1.) (-)-Ipc2BH, 2.) aq. H2O2, aq. NaOH / 1.) THF, -25 deg C, 6 h, 2.) THF, RT, 5 h View Scheme

1: 1.) n-BuLi, 2.) CuI 2: 73 percent / DIBAL / toluene / 5 h / -78 °C 3: 1.) NaH, 2.) n-Bu4NHSO4 / 1.) THF, 2.) THF, RT, 10 h 4: 1.) (-)-Ipc2BH, 2.) aq. H2O2, aq. NaOH / 1.) THF, -25 deg C, 6 h, 2.) THF, RT, 5 h View Scheme

1: 1.) NaH, 2.) n-Bu4NHSO4 / 1.) THF, 2.) THF, RT, 10 h 2: 1.) (-)-Ipc2BH, 2.) aq. H2O2, aq. NaOH / 1.) THF, -25 deg C, 6 h, 2.) THF, RT, 5 h View Scheme

1: 1.) dibutyltin oxide, 2.) cesium fluoride / 1.) chloroform/methanol, reflux, 24 h, 2.) DMF, 24 h, room temperature; 50 deg C, 1 h 2: 92 percent / NaH / tetrahydrofuran 3: 1.) (-)-diisopinocamphenylborane, 2.) 30 percent H2O2, NaOH / 1.) THF, 2.) water View Scheme

sodium hydroxide; dihydrogen peroxide; dIpc2BH 1.) THF, -25 deg C, 6 h, 2.) THF, RT, 5 h; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;

sodium hydroxide; dihydrogen peroxide; (Ipc)2BH 1.) THF, 2.) water; Yield given. Multistep reaction;