1: Et3N / CH2Cl2 / 0 °C 2: 70 percent / LiHMDS / tetrahydrofuran / -78 - -5 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: 75 percent / 2,4-dinitrobenzenesulfenyl chloride; Et₃N / 1,2-dichloro-ethane / 90 &deg;C<br />2: Cs₂CO₃ <br /> <br /> &nbsp;