1: 91 percent / Na, liq. NH3 / tetrahydrofuran / 1 h / -78 °C 2: pyridinium dichromate / dimethylformamide / 1.) 0 deg C, 1 h, 2.) RT, 4 h 3: diethyl ether 4: 0.1 N HCl / methanol / 24 h View Scheme

<b>Multi-step reaction with 3 steps<br /> </b>1: K-hexamethyldisilazide / 1.) THF, toluene, 20 min, RT, 2.) a) - 78 deg C, 1 h, b) RT, 1 h<br />2: 70 percent HClO₄ / diethyl ether / 0.67 h / - 30 deg C to RT<br />3: K-hexamethyldisilazide / 1.) THF, toluene, 20 min, RT, 2.) a) -78 deg C, b) RT, 30 min<br /> <br /> &nbsp;