72 h;

<b>Multi-step reaction with 2 steps<br /> </b>1: 60 percent / Et₃N; 4-tolylselenoamide / 1.5 h / 0 &deg;C<br />2: 93 percent / NaIO₄ / dimethylformamide / 0.02 h / Heating<br /> <br /> &nbsp;