trifluorormethanesulfonic acid in tetrachloromethane; cyclohexane T=20°C; 2.5 h; Title compound not separated from byproducts;

1: With trifluorormethanesulfonic acid in tetrachloromethane; cyclohexane T=20°C; 2.5 h; 2: With tetrabutyl ammonium fluoride in tetrahydrofuran T=20°C; 2.5 h;

oxalyl dichloride; dimethyl sulfoxide; triethylamine in dichloromethane T=-78 - -55°C; 2 h;

1.1: 4-(N,N-dimethlyamino)pyridine; pyridine 3.1: diisobutylaluminium hydride 4.1: sec.-butyllithium / tetrahydrofuran; cyclohexane / 1 h / -78 °C / |Inert atmosphere 4.2: -78 - 20 °C / |Inert atmosphere 5.1: tetrahydrofuran / 20 °C / |Inert atmosphere 6.1: NaBO3*4H2O / tetrahydrofuran; water / 2 h / 20 °C / |Inert atmosphere View Scheme