Stereoselective Double Spirocyclization of 2-Benzyl-3-alkynyl Chromone with Nitrone via Gold-Catalyzed Cascade Reactions

• DOI: 10.1021/acs.orglett.4c02338
• Publication Date: 2024-07-25T17:00:43Z
• Authors: Amit Vijay Sasane; Chun-Tang Chiou; Ming-Yiang Chang; Wen-Tai Li
• Keywords: Chromone; Nitrone

A novel, highly stereoselective gold-catalyzed spirocyclization of 2-benzyl-3-alkynyl chromone with nitrone is described. This cascade reaction involves cycloisomerization, nitrone-olefin [3 + 2]-annulation, alkene oxidation, and rearrangement for the formation spirocyclic products. Interestingly, isoxazolidine ring generated from 2]-annulation donates oxygen to generate a new pyran-3(4