1: sodium methylate / methanol 2: toluene-4-sulfonic acid / methanol; dichloromethane View Scheme

<b>Multi-step reaction with 3 steps<br /> </b>1: tetrahydrofuran<br />2: pyridine<br />3: diethylazodicarboxylate; triphenylphosphine / tetrahydrofuran / 20 &deg;C<br /> <br /> &nbsp;