trifluorormethanesulfonic acid in toluene T=27°C; 12 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

<b>Multi-step reaction with 2 steps<br /> </b>1: 82 percent / dimethylformamide<br />2: 1.) n-BuLi / 1.) THF, O deg C, 10 min, 2.) -78 deg C<br /> <br /> &nbsp;