Scheme 8.

Synthesis of Lukianol A (56)^a

^a Reagents and conditions: (i) H₂O₂, NaOH, EtOH/H₂O, 0 °C, 98%; (ii) (1) BF₃·Et₂O, Et₂O, reflux; (2) NH₂OH·HCl, pyridine, EtOH, reflux, 67% (over 2 steps); (iii) H₂ (1 atm), Pd (5%)/C, THF, 94%, (Z):(E) = 1:1; (iv) ClOCCO₂Me, pyridine, THF, 73%, (Z):(E) = 2.5:1; v, Ti–graphite (TiCl₃:C₈K = 1:2), DME, reflux, 52%; (vi) p-MeO–C₆H₄COCH₂Br, K₂CO₃, acetone, reflux, 91%; (vii) (1) KO–tBu, H₂O, Et₂O, 0 °C; (2) Ac₂O, NaOAC, reflux, 59% (over 2 steps); (viii) BBr₃, CH₂Cl₂, −78 °C, 99%. (Reprinted with permission from ref 53. Copyright 1995 American Chemical Society.)