have developed a one-pot synthesis of benzo[b]fluorenones via a cobalt-catalyzed [3+2] annulation of oxabicyclic alkenes followed by a ring-opening/dehydration sequence in good to excellent yields. With the use of 2-(1-methylhydrazinyl)pyridine (MHP), first explored by our group as the bidentate directing group in C–H functionalization of benzoic hydrazides, the new reaction sequence proceeded smoothly
我们已经开发了一种通过一锅合成的苯并[ b ]芴酮的方法,该方法是通过钴催化的氧杂双环烯烃的[3 + 2]环化反应,然后以开环/脱水顺序进行的,收率很好。我们小组首先探索使用2-(1-甲基肼基)吡啶(MHP)作为苯甲酰肼的CH官能化中的双齿导向基团,新的反应顺序进行得很顺利,并能耐受各种官能团,具有便利的可扩展性。值得注意的是,氧气在反应系统中充当绿色氧化剂。仔细调整反应参数可确保通过二氢环氧苯并芴酮中间体的芳构化直接合成苯并[ b ]芴酮。