Skeletal Reorganization of Cycloalkylamines Into Angular Azatetracyclic Scaffolds
Yun-Peng Wang1, Wujiong Xia2, Bao-Kuan Guo1
1School of Pharmaceutical Sciences, School of Chemistry and Chemical Engineering, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, State Key Laboratory of Synergistic Chem-Bio Synthesis, Shanghai Jiao Tong University, Shanghai, China.
Angewandte Chemie (International Ed. in English)
|July 17, 2026
Summary
Chemists developed a new borane-catalyzed reaction to efficiently create complex angular azatetracycles. This single-step method rapidly builds challenging molecular frameworks with multiple stereocenters.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Catalysis
Background:
- Constructing angular azatetracyclic frameworks with vicinal quaternary stereocenters is synthetically challenging.
- Existing methods often require multiple steps and lack efficiency.
Purpose of the Study:
- To develop a novel, efficient, single-step method for synthesizing angular azatetracyclic frameworks.
- To explore a borane-catalyzed cascade reorganization for complex molecule synthesis.
Main Methods:
- Utilized borane catalysis, specifically B(C6F5)3, for a cascade reaction.
- Employed N-cycloalkylidenyl (CAD)-substituted aryl cycloalkylamines as substrates.
- Investigated reaction mechanisms using experimental data and DFT calculations.
Main Results:
- Achieved the first borane-catalyzed cascade reorganization of CAD-substituted aryl cycloalkylamines.
- Successfully synthesized densely functionalized angular/fused azatetracycles with high diastereoselectivity.
- Demonstrated a cascade involving α-hydride abstraction, aza-6π electrocyclization, double ring expansion, and hydride rebound.
Conclusions:
- The developed cascade reaction provides rapid access to challenging azatetracyclic architectures.
- The method efficiently forges multiple C-C bonds and stereocenters in one operation.
- The reaction exhibits broad substrate scope and high efficiency, validated by mechanistic studies.
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