1: TFA / tetrahydrofuran; H2O / 16 h 2: Pb(OAc)4, Na2CO3 3: benzene / 75 - 80 °C 4: NaH / benzene / 1 h / Ambient temperature 6: n-BuLi / tetrahydrofuran; hexamethylphosphoric acid triamide 7: 1.) (nBu)4NF 2.) H2O / 1.) THF View Scheme

1: 83 percent / aq. TFA / tetrahydrofuran / Ambient temperature 2: 91 percent / Na2CO3, Pb(OAc)4 / CH2Cl2 / 0.25 h / -78 °C 3: 55 percent / toluene / 3 h / 80 °C 4: lithium hexamethyldisilazane (LiHMDS) / tetrahydrofuran; hexamethylphosphoric acid triamide / 1 h / -78 - 0 °C 5: NaHCO3 / tetrahydrofuran; hexamethylphosphoric acid triamide / 1 h / Ambient temperature 6: 74 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / Ambient temperature 7: 95 percent / LiOH / 1,2-dimethoxy-ethane; H2O / Ambient temperature View Scheme