Scheme 1

Methods for the synthesis of compounds 5a–e and 10a–f. Reagents and conditions: a H₂O, r.t., 2–5 h. b CuBr (1 mmol), Et₃N (1 mmol), DMF (5 ml), 80°, 8–10 h. c K₂CO₃ (1 mmol), EtOH (10 ml), reflux, 12–24 h. d CuI (7 mol%), H₂O/t-BuOH (1:1), Et₃N (1.3 mmol), r.t., 20–24 h