1: pyridinium chlorochromate (PCC), sodium acetate / CH2Cl2 / 1.5 h / Ambient temperature 2: 1.) t-BuOK / 1.) DMF, RT, 5 min, 2.) a) RT, 20 h, b) 90 deg C, 1 h View Scheme

1: (3-(methoxycarbonyl)propyl)triphenylphosphonium bromide With sodium hexamethyldisilazane in tetrahydrofuran T=-20°C; 0.333333 h; Inert atmosphere; 2: isobutyraldehyde in tetrahydrofuran T=-78 - 20°C; Inert atmosphere;

1.1: acetonitrile / 6 h / Reflux; Inert atmosphere 2.1: sodium hexamethyldisilazane / tetrahydrofuran / 0.33 h / -20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere View Scheme

potassium tert-butylate 1.) DMF, RT, 5 min, 2.) a) RT, 20 h, b) 90 deg C, 1 h; Multistep reaction;