4 遷移金属錯体による炭素-炭素結合形成反応を鍵段階とした(-)-mesembrineの合成(口頭発表の部)

概要

論文の詳細を見る
4-Arylhexahydroindole derivatives 5 were synthesized from 2-arylcyclohexenyl allylamine derivatives 4, which have a large protecting group on nitrogen, using zirconium-promoted cyclization. Reaction of 4e with Cp_2ZrBu_2 followed by treatment with MeMgBr and then O_2 gave 2a in 63% yield by a one-pot reaction, since the approach of O_2 to zirconium was prevented by the aryl group. The total syntheses of (±)-mesembrane and (±)-mesembrine were achieved starting from 2a. To synthesize these natural products in a chiral form, the starting allylamine derivative 24 (80% yield, 86%ee, recrystallized from MeOH, 99%ee with 79% recovery) was prepared from allyl carbonate 22a and N-tosylallylamine 23 using palladium-catalyzed asymmetric amination in the presence of (S)-BINAPO as a chiral ligand. (-)-Mesembrane and (-)-mesembrine were synthesized from this allylamine 24.
天然有機化合物討論会の論文
1997-07-20