Conjugated Nitroolefins as Twofold Electrophiles for the Assembly of Five-Membered Monoheterocycles via MIRC [3+2] Annulation: An Update on Synthetic and Mechanistic Aspects

Five-membered monoheterocycles, either isolated or embedded in more complex systems, are ubiquitous structural motifs in nature and hence privileged targets of synthetic chemistry. Among a plethora of methodologies used for their assembly, [3+2] annulation strategies keep attracting particular interest among chemists, partly because of some significant characteristics from both the operative and the environmental viewpoints. Herein, the extensive use of conjugated nitroolefins as twofold electrophilic, two-carbon components of [3+2] MIRC (Michael-Initiated Ring Closure) annulations is reviewed as a practical and mechanistic update covering the last decade (2015–2025).