1: BH3 / tetrahydrofuran / 6 h / 20 °C 2: 40 percent / aq. Na2CO3 / tetrahydrofuran / 6 h / 0 °C View Scheme

silver perchlorate in dichloromethane T=20°C; 1 h;

borane in tetrahydrofuran T=20°C; Reduction; cyclization; 6 h;

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '472690', constants.ctx, '0')">toluene-4-sulfonic acid</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1718733', constants.ctx, '0')">ethanol</a> <br />T=20&deg;C;&nbsp;44.5&nbsp;h;&nbsp;<br /> <br /> &nbsp;