Pd(0)-Catalyzed Dearomative Diarylation of Indoles
David A Petrone1, Masaru Kondo2, Nicolas Zeidan1
1Department of Chemistry, University of Toronto, 80 St. George St., Toronto, M5S 3H6, Canada.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 7, 2016
Summary
Researchers developed a new Pd(0)-catalyzed reaction for indole diarylation using boroxines. This method efficiently produces fused indolines, minimizing unwanted Suzuki coupling side reactions.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Indole derivatives are crucial scaffolds in medicinal chemistry.
- Dearomative functionalization offers novel synthetic routes to complex molecules.
- Developing selective methods for indole diarylation remains a challenge.
Purpose of the Study:
- To establish a palladium(0)-catalyzed protocol for the dearomative 1,2-diarylation of indoles.
- To utilize readily available boroxines as coupling partners.
- To achieve selective formation of fused indolines over direct Suzuki coupling.
Main Methods:
- Developed a Pd(0)-catalyzed reaction system.
- Employed triphenylphosphine (PtBu3) as a ligand.
- Utilized various substituted indoles and boroxines as substrates.
Main Results:
- Achieved efficient dearomative syn 1,2-diarylation of indoles.
- Successfully synthesized fused indolines in moderate to excellent yields.
- Obtained all products as single diastereomers.
- Minimized the extent of direct Suzuki coupling.
Conclusions:
- The developed protocol offers a versatile and efficient method for synthesizing complex indole derivatives.
- The reaction's selectivity can be influenced by steric and electronic properties of substrates and coupling partners.
- This methodology provides a valuable tool for accessing novel fused indoline structures.
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