1: pyridinium chlorochromate / CH2Cl2 / 18 h / 25 °C 2: 7.5 M KOH / tetrahydrofuran; methanol; H2O / 48 h / 25 °C 3: 96 percent / 10percent DMAP / pyridine / 3 h / 70 °C 4: 89 percent / H2 / Lindlar catalyst 5: 72 percent / BF3*Et2O 6: H2 / PtO2 7: KOH / tetrahydrofuran; methanol; H2O / 48 h / 25 °C View Scheme

<b>Multi-step reaction with 4 steps<br /> </b>2: diisobutylaluminium hydride<br />3: oxalic acid / tetrahydrofuran / Linde 4A molecular sieves<br />4: 82 percent / 1.) titanium tetrachloride, 2,4,6-trimethylpyridine, 2.) 1 M hydrochloric acid / CH₂Cl₂ / 1.) -78 degC, 5 min., 2.) -78 degC to r.t.<br /> <br /> &nbsp;