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Redox-Neutral Dearomative Spirocyclization of Isoxazoline N-Oxides: A Route to Structural Analogs of Tyrosine-Derived

Roman S Malykhin¹, Duc Huy Nguyen^1,2, Alexey Yu Sukhorukov¹

¹Laboratory of Organic and Metal-Organic Nitrogen-Oxygen Systems (LOMONOS), N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow 119991, Russian Federation.

The Journal of Organic Chemistry

|October 1, 2025

Abstract:

A novel synthetic route to spirocyclic isoxazolines based on a redox-neutral dearomative cyclization of 3-benzyl-substituted isoxazoline N-oxides has been developed. The reaction likely proceeds through isoxazoline ring opening with generation of an unstable N-oxoiminium cation. The latter acts as an O-electrophile in the cyclization involving the ipso-position of the aryl ring. The reaction exhibits a broad substrate scope and affords spirocyclic isoxazolines featuring novel substitution patterns compared with those accessible by synthetic methods or found in natural sources.

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