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Total Synthesis and Absolute Structure Assignment of (+)-Itomanallene B
Rodney A Fernandes1, Ravikant S Ranjan1
1Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra 400076, India.
The Journal of Organic Chemistry
|June 25, 2026
Summary
This study reports the asymmetric synthesis of itomanallene B and its analogues, enabling structural revision. The developed synthetic strategy efficiently creates substituted tetrahydrofuran (THF) acetogenins.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Natural Product Synthesis
Background:
- Itomanallene B is a complex natural product with a substituted tetrahydrofuran (THF) core.
- Previous synthetic routes may not have fully addressed stereochemical complexities or provided efficient access to analogues.
Purpose of the Study:
- To achieve the asymmetric total synthesis of (+)-itomanallene B and related stereoisomers.
- To revise the structure of itomanallene B based on synthetic outcomes.
- To develop a versatile synthetic platform for THF acetogenins.
Main Methods:
- Asymmetric dihydroxylation to establish syn-diol centers.
- Biomimetic brominative cyclization for syn-THF ring and allene installation.
- Tsuji-Trost cyclization for trans-THF ring construction.
- Corey-White-Posner reaction for installing the bromoallene moiety.
Main Results:
- Successful asymmetric total synthesis of (+)-itomanallene B, (-)-1,4-diepi-itomanallene B, and two other stereoisomers.
- Structural revision of itomanallene B confirmed through synthesis.
- Efficient construction of both syn- and trans-THF ring systems.
- Installation of the characteristic allene moiety.
Conclusions:
- The reported synthetic approach is efficient and versatile.
- This methodology provides a robust platform for synthesizing diverse THF acetogenins and their analogues.
- The study contributes to the understanding of itomanallene B's structure and synthesis.
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