1.1: bis(trimethylsilyl)acetamide / 1-methyl-pyrrolidin-2-one / 80 °C 1.2: 70 percent / TMSOTf / 1-methyl-pyrrolidin-2-one / 24 h / 0 °C 2.1: 87 percent / aq. NaOH / 3 h / 20 °C 3.1: 10 percent / DIBAL-H / tetrahydrofuran / 48 h / 20 °C View Scheme

1.1: bis(trimethylsilyl)acetamide / dimethylformamide / 1.5 h / 20 °C 1.2: 81 percent / TMSOTf / dimethylformamide / 3 h / 0 - 5 °C 2.1: 42 percent / aq. NaOH / dioxane / 4 h / 20 °C 3.1: DIBAL-H / tetrahydrofuran / 24 h / 20 °C 4.1: NEt3; DMAP / CH2Cl2 / 2 h / Heating View Scheme

1.1: bis(trimethylsilyl)acetamide / dimethylformamide / 1.5 h / 20 °C 1.2: 81 percent / TMSOTf / dimethylformamide / 3 h / 0 - 5 °C 2.1: 42 percent / aq. NaOH / dioxane / 4 h / 20 °C 3.1: DIBAL-H / tetrahydrofuran / 24 h / 20 °C 4.1: NEt3; DMAP / CH2Cl2 / 2 h / Heating 5.1: 81 percent / hydrogen; NEt3 / Pd/C / ethyl acetate / 4 h / 50 °C / 760 Torr View Scheme

1.1: bis(trimethylsilyl)acetamide / dimethylformamide / 1.5 h / 20 °C 1.2: 81 percent / TMSOTf / dimethylformamide / 3 h / 0 - 5 °C 2.1: 42 percent / aq. NaOH / dioxane / 4 h / 20 °C 3.1: DIBAL-H / tetrahydrofuran / 24 h / 20 °C View Scheme