Gold(I)-Catalyzed Heteroannulation of Salicylic Amides with Alkynes: Synthesis of 1,3-Benzoxazin-4-one Derivatives
Masahiro Abe*, Megumu Kawamoto, Mayu Inoue, Tetsutaro Kimachi and Kiyofumi Inamoto*
*Mukogawa Women’s University, 11-68, 9-Bancho, Koshien, Nishinomiya, Hyogo 663-8179, Japan,
Email: abe_111mukogawa-u.ac.jp, inamoto
mukogawa-u.ac.jp
M. Abe, M. Kawamoto, M. Inoue, T. Kimachi, K. Inamoto, Org. Lett., 2022, 24, 5684-5687.
DOI: 10.1021/acs.orglett.2c02066
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Abstract
A gold(I)-catalyzed heteroannulation of salicylic amides with alkynes provides a broad range of variously substituted benzoxazinones containing quaternary carbon centers. The method offers a high functional group tolerance and excellent atom economy.
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proposed mechanism
Details
The document discusses a study on the gold(I)-catalyzed heteroannulation of salicylic amides with alkynes to synthesize 1,3-benzoxazin-4-one derivatives. This method offers an efficient and straightforward approach to constructing heterocyclic compounds, showcasing high functional group tolerance and excellent atom economy. The study highlights the optimization of reaction conditions using N-methyl salicylic amide and phenylacetylene as model substrates, with toluene identified as the most suitable solvent. The optimal conditions involved using 2 mol % of IPrAuCl and AgOTf, achieving a 98% yield. The scope of the reaction was explored with various salicylic amides and alkynes, demonstrating good yields with different substituents. The proposed mechanism involves the activation of the alkyne by the cationic gold catalyst, followed by nucleophilic attack and cyclization to form the benzoxazinone. This method provides a new route for synthesizing benzoxazinones, which are important in bioactive molecules. The study was conducted by researchers from Mukogawa Women’s University and supported by JSPS KAKENHI. The authors declare no competing financial interests. Further details, including experimental procedures and characterization data, are available in the supporting information.
Key Words
ID: J54-Y2022