Scheme 11.

Reaction conditions: (a) CH₂=PPh₃, THF, 45°C, 10 h; then COCl₂, Me₂SO, CH₂Cl₂, –78°C, 20 min, Et₃N, –78°C to rt; (b) vinyl magnesium bromide, MgBr₂·OEt₂, –78°C, CH₂Cl₂, 3 h; (c) (CyP)₂RuCl₂(CHPh), 10 mol %, CH₂Cl₂, 15 min, 99%; (d) BnBr, DMF, NaH, 94%; (e) OsO₄, NMO, Me₂C=O/H₂O, 93%; (f) TIPS-Cl, DMF, AgNO₃, Separate compounds, (yield not given for this step, but 54% over 3 preceding steps); (g) O₃, CH₂Cl₂, pyridine, then Me₂S, (h) SmI₂, tert-BuOH, THF, –78°C, 3 h, then 20°C, O/N.