Diverse Synthesis of Fused Polyheterocyclic Compounds via [3 + 2] Cycloaddition of In Situ-Generated Heteroaromatic <i>N</i>-Ylides and Electron-Deficient Olefins

Abstract

[3 + 2] Cycloaddition reactions of heteroaromatic N-ylides with electron-deficient olefins have been developed. The heteroaromatic N-ylides, in situ generated from N-phenacylbenzothiazolium bromides, can smoothly react with maleimides under very mild conditions, affording fused polycyclic octahydropyrrolo[3,4-c]pyrroles in good-to-excellent isolated yields. This reaction concept could also be extended to 3-trifluoroethylidene oxindoles and benzylidenemalononitriles as electron-deficient olefins for accessing highly functionalized polyheterocyclic compounds. A gram-scale experiment was also carried out to verify the practicability of the methodology.

Keywords

• [3 + 2] cycloaddition
• diverse synthesis
• heteroaromatic <i>N</i>-ylides
• electron-deficient olefins
• fused polyheterocycles