Reagents and conditions: (i) a: t-BuLi, THF (−78-0 °C, 30 min); b: BuTeTeBu (r.t., 3 h); (ii) SO2Cl2 or Br2, THF (0 °C, 15 min); (iii) NaBH4, MeOH (r.t., 1h); (iv) vinyl acetate, CAL-B, hexane (32 °C, 7 h); (v) K2CO3, MeOH, H2O (r.t. overnight); (vi) a: n-BuLi. TMEDA, pentane (reflux, 24 h), b: BuTeTeBu (0 °C - r.t., 2 h); (vii) a: NaH, THF (0 °C, 30 min), b: MeI (r.t., 2 h).