Scheme 2.

Reagents and conditions: (a) Me₂SO₄, K₂CO₃, acetone; (b) Br₂, CHCl₃, 77% (two steps); (c) HC≡CSiMe₃, Pd(PPh₃)₂Cl₂, Cul, PPh₃, piperidine; (d) K₂CO₃, MeOH, 71% (two steps); (e) n-BuLi, I(CH₂)₄I, THF, HMPA, - 78°→r.t., 42%; (f) CHCl₃, n-BuLi, THF, -78°C, 86%; (g) BBr₃, CH₂Cl₂, - 78°C→r.t.; (h) FeCl₃, THF, 23% (two steps); (i) CAN in aq. acetonitrile, 81% (10) or 89% (9)