Scheme 7.

Convergent Synthesis of Lamellarins O (52) and Q (54) and Lukianol A (56)^a

^a Reagents and conditions: (i) NBS (3 equiv), THF, −78 °C, 1 h then 20 °C for 4 h; (ii) PhLi (1 equiv), −78 °C, 0.16 h then ClCO₂Me (1.05 equiv), −78 to 20 °C, 1 h; (iii) Pd(PPh₃)₂Cl₂ (10 mol %), 1,4,-dioxane, 101 °C, 14 h; (iv) Bu₄NF (10 mol % excess), THF, 20 °C, 1 h then 0.5 M aq.HCl; (v) p-MeOC₆H₄COCH₂Br (3 equiv.), K₂CO₃ (5 equiv.), Bu₄NCl (20 mol %), THF, 66 °C, 7 h; (vi) Pd(PPh₃)₄ (5 mol %), satd aq. Na₂CO₃ (6 equiv), DMF, 153 °C, 23 h; (vii) see ref 53. (Reprinted with permission from ref 47. Copyright Royal Society of Chemisty 1997.)