摘要
A Pd(II)-catalyzed [5 + 2] annulation between N-triflyl aryl indoles and α,γ-substituted allenoates for the synthesis of indole-fused benzodiazepines is reported. This protocol is highly efficient when N-acetylated valine amino acid and DMSO have been used as ligand and cosolvent, respectively. The substrate scope can be further extended to disubstituted allenoates. A reaction mechanism has been proposed based on the mechanistic studies. Mechanistically, the N-acetylated valine amino acid ligand accelerates C-H activation of the C(sp2)-H bond. Consequent cyclopalladation leads to the formation of a six-membered palladacycle. Subsequent coordination and migratory insertion of an allenoate forms the possible eight-membered intermediate. Reductive elimination followed by a [1,3]-H shift results in the indole-fused benzodiazepines.
原文 | English |
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頁(從 - 到) | 6246-6250 |
頁數 | 5 |
期刊 | Organic Letters |
卷 | 25 |
發行號 | 34 |
DOIs | |
出版狀態 | Published - 1 9月 2023 |