1: LiEt3BH / tetrahydrofuran / 1.17 h / Heating 2: (COCl)2, DMSO 3: potassium tert-butoxide / tetrahydrofuran / -78 deg C -> r.t. 4: 1.) Cp2ZrCl2, 2.) I2 / 1.) dichloroethane, 23,5 h, 2.)THF, -25 deg C to -10 deg C, 140 min 5: 84 percent / Ag2CO3, triethylamine / Pd(OAc)2 / CH2Cl2; ethanol / 1.25 h 6: 1.) 2,2,6,6-tetramethyl-1-oxopiperidinium chloride, 2.) NaClO2, NaH2PO4*H2O / 1.) CH2Cl2, -20 deg C, 10 min, then -15 deg C, 2 h, 2.) 2-methylbutene, H2O 7: 70 percent / benzenesulfonyl chloride, pyridine / 18.5 h / 0 - 10 °C 8: 78 percent / aq. HF / tetrahydrofuran / 8.5 h View Scheme

<b>Multi-step reaction with 9 steps<br /> </b>1: 1.) NaH, 2.) tetrabutylammonium iodide / 1.) THF, r.t., 30 min, 2.) 55-60 deg C, 23 h<br />2: 1.) NaH, 2.) tetrabutylammonium iodide / 1.) THF, 62 deg C, 1,5 h, 2.) THF, 62 deg C, 20 h<br />3: 68 percent / BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 30 min, 2.) -20 deg C, 45 min<br />4: 77 percent / Ph₃P, pyridine, diethyl azodicarboxylate / tetrahydrofuran / 5 h / -45 deg C to 0 deg C<br />5: 91 percent / K₂CO₃ / methanol / 2.5 h<br />7: 1.) O₃, 2.) NaBH₄ / 1.) CH₂Cl₂, MeOH, -78 deg C, 2.) -&gt; r.t., overnight<br />8: pyridine, 4-(N,N-dimethylamino)pyridine / 2 h / 0 &deg;C<br />9: diisopropylethylamine / CH₂Cl₂ / 0.5 h / 0 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1: pyridine, 4-(N,N-dimethylamino)pyridine / 2 h / 0 &deg;C<br />2: diisopropylethylamine / CH₂Cl₂ / 0.5 h / 0 &deg;C<br /> <br /> &nbsp;