1: n-BuLi / tetrahydrofuran; hexamethylphosphoric acid triamide / 30 h / 23 °C 2: NaI / acetone / 65 h / Heating 3: 1.) Mg, 2.) CuI / 1.) THF, reflux, 3 h, 2.) 30 min, ice bath, 3.) 23 deg C, 30 min 4: tetra-n-butylammonium fluoride / tetrahydrofuran / 1 h / 23 °C 5: 68 percent / CrO3, 6 N H2SO4 / acetone / 3.5 h, ice-cold then RT 6: diethyl ether View Scheme

1: 68 percent / CrO3, 6 N H2SO4 / acetone / 3.5 h, ice-cold then RT 2: diethyl ether View Scheme

1: tetra-n-butylammonium fluoride / tetrahydrofuran / 1 h / 23 °C 2: 68 percent / CrO3, 6 N H2SO4 / acetone / 3.5 h, ice-cold then RT 3: diethyl ether View Scheme

in diethyl ether