1: 1.) O3, 2.) Me2S / 1.) CH3OH, CH2Cl2, -78 deg C 2: NaH / 1,2-dimethoxy-ethane / 0 - 20 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: NaBH₄ / methanol / 0 &deg;C<br />2: pyridine / Ambient temperature<br /> <br /> &nbsp;