An Efficient and Short Total Synthesis of (−)‐Heliannuol A by Intramolecular Ullmann C−O Coupling for the Construction of an Eight‐Membered Ether Ring. Issue 17 (4th May 2021)

• Record Type: Journal Article
• Authors: Tsubogo, Tetsu; Okamura, Fumiya; Omori, Akiho; Uchiro, Hiromi
• Is Part Of: ChemistrySelect. Volume 6:Issue 17(2021)
• Page Start: 4224
• Page End: 4228
• Publication Date: 2021-05-04
• Subjects: Heliannuol A -- eight-membered cyclic ether -- Ullmann coupling -- cyclization -- total synthesis; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202100355
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Herein, we report a method for the synthesis of eight‐membered cyclic ethers by a direct C−O bond connection using an intramolecular Ullmann coupling reaction based on our previously published methodology. We found that allelopathically active heliannuol A could be rapidly synthesised using this method. The use of a strongly coordinating 4‐pyrrolidinopyridine ligand accelerates the reaction rate and leads to the C−O coupling reaction of a typically inaccessible sterically bulky tertiary alcohol. Furthermore, this method circumvents the protection and deprotection steps, presenting a new strategy for the syntheses of benzannulated eight‐membered ring structures. Abstract : We present a method for the synthesis of an eight‐membered cyclic ether with the direct formation of C−O bonds through an intramolecular Ullmann coupling reaction. We report the rapid synthesis of allelopathically active heliannuol A using the proposed method. Furthermore, we circumvent the conventional protection and deprotection steps. Overall, this approach is an easy, efficient, and simple way to generate an eight‐membered cyclic ether and is a new strategy for synthesising benzannulated eight‐membered ring structures.