Water-Promoted Indole Migration of Bis(indol-3-yl)-ynamides Using Zn(OTf)2 as a Lewis Acid Catalyst
Zhanshuai Xiao1, Yin Wei1, Min Shi1
1State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, University of Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, People's Republic of China.
A novel zinc(II)-catalyzed reaction efficiently synthesizes carbonyl-containing bisindole derivatives using bis(indol-3-yl)-ynamides. This method offers broad scope and functional group tolerance for creating valuable organic compounds.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Bisindole derivatives are important scaffolds in medicinal chemistry.
- Efficient synthetic routes to functionalized bisindoles are highly sought after.
Purpose of the Study:
- To develop a novel zinc(II)-catalyzed cycloisomerization for bisindole synthesis.
- To explore the reaction mechanism and scope for constructing carbonyl-containing bisindole derivatives.
Main Methods:
- Zinc(II)-catalyzed cycloisomerization of bis(indol-3-yl)-ynamides in water.
- Isotope 18O-labeling experiments to elucidate reaction mechanism.
- Large-scale synthesis and further functionalization of products.
Main Results:
- Successful construction of carbonyl-containing bisindole derivatives in moderate to good yields.
- Demonstrated broad substrate scope and good functional group tolerance.
- Identified a 7-endo-dig cyclization followed by a pseudo-1,6-indole-migration mechanism.
Conclusions:
- A new, efficient, and versatile method for synthesizing bisindole derivatives has been established.
- The developed methodology is suitable for large-scale synthesis and further chemical transformations.
- This work provides a valuable tool for accessing complex bisindole structures.
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