N,N,N',N',N'',N''-hexamethylphosphoric triamide; tert-butyldimethylsilyl chloride; lithium hexamethyldisilazane in tetrahydrofuran T=-78 - 20°C; Ireland-Claisen rearrangement; 1.33333 h;

1: 76 percent / NaBH4 / ethanol / 3 h / 20 °C 2: 84 percent / DMAP; pyridine / CH2Cl2 / 3 h / cooling 3: 74 percent / HMPA; tert-butyldimethylsilyl chloride; LHMDS / tetrahydrofuran / 1.33 h / -78 - 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / 0.17 h / -78 °C 1.2: tetrahydrofuran; hexane / 0.17 h / -78 °C 2.1: 3.57 g / bromine / CH2Cl2 / 0.17 h / -78 °C 3.1: 76 percent / NaBH4 / ethanol / 3 h / 20 °C 4.1: 84 percent / DMAP; pyridine / CH2Cl2 / 3 h / cooling 5.1: 74 percent / HMPA; tert-butyldimethylsilyl chloride; LHMDS / tetrahydrofuran / 1.33 h / -78 - 20 °C View Scheme

1: 3.57 g / bromine / CH2Cl2 / 0.17 h / -78 °C 2: 76 percent / NaBH4 / ethanol / 3 h / 20 °C 3: 84 percent / DMAP; pyridine / CH2Cl2 / 3 h / cooling 4: 74 percent / HMPA; tert-butyldimethylsilyl chloride; LHMDS / tetrahydrofuran / 1.33 h / -78 - 20 °C View Scheme

1: 84 percent / DMAP; pyridine / CH2Cl2 / 3 h / cooling 2: 74 percent / HMPA; tert-butyldimethylsilyl chloride; LHMDS / tetrahydrofuran / 1.33 h / -78 - 20 °C View Scheme