No abstract

We represented herein a two-step synthesis of 1-methyl-6H-indol-6-one (1) which is an N-containing 6/5 fused bicyclic building blocks in Amaryllidaceae alkaloids. The key step featured with a “one-pot” ozonolysis/reductive amination/cyclization of allylated 1,3-cyclohexadione (6) to give bicyclic compounds (1). Moreover, the formal total synthesis of natural product γ-lycorane could be achieved through a photo-promoted cyclization/oxidation cascade reaction from the resulting bicyclic intermediate 1h.