1: 83 percent / H2 / PtO2 Adams catalyst / ethyl acetate / 3.5 h / 20 °C / 1810.02 - 2068.59 Torr 2: 93 percent / triethylamine / CH2Cl2 / 0.5 h / 0 - 20 °C 3: 91.5 percent / sodium azide / dimethylformamide / 5 h / 68 - 70 °C 4: 98 percent / H2 / PtO2 Adams catalyst / methanol / 3.5 h / 20 °C / 1810.02 - 2068.59 Torr View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '10775048', constants.ctx, '0')">titanium(IV) isopropylate</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '1903730', constants.ctx, '0')">trimethylsilylazide</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '8489014', constants.ctx, '0')">(-)-(4S,6S,8R)-8-(hydroxymethyl)-1,7-dioxaspiro[5.5]undecan-4-ol</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1730800', constants.ctx, '0')">dichloromethane</a> <br />T=-20&deg;C;&nbsp;Ring cleavage;&nbsp;48&nbsp;h;&nbsp;&nbsp;Product distribution;&nbsp;<br /> &nbsp;