Divergent [4+3] Annulations of β'-Acetoxy Allenoates: Access to Azepino[1,2-a]indole Derivatives
Yannan Zhu1,2, You Huang1
1State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Abstract:
In this work, the Lewis base-catalyzed divergent [4 + 3] annulation reactions of β'-acetoxy allenoates with two different indole derivatives are reported. A wide range of azepino[1,2-a]indole derivatives was smoothly obtained from 2-((3-formyl-1H-indol-2-yl)methyl)malonates by employing the DABCO catalyst. The syntheses of two regioselective diazepino[1,2-a]indole derivatives from 3-formyl-1H-indole-2-carboxamides are realized by the catalysis of DABCO and organophosphine, respectively. A series of functional group transformations can be achieved in the three 1,2-fused seven-membered indole products.
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