Literature review reveals diverse catalytic pathways in itaconimide annulations for constructing complex rings, highlighting gaps in sustainable metric assessment.
Key Points
To critically review catalytic annulation pathways of terminal-methylene itaconimides and identify opportunities for more sustainable, selective synthetic applications.
Evaluated catalyst-free, organocatalytic, phosphine-catalyzed, transition-metal-catalyzed, and visible-light photoredox annulation reactions of 3-methylenepyrrolidine-2,5-diones.
Analyzed mechanistic roles of the exocyclic alkene as a dipolarophile, electrophilic addition site, radical acceptor, and migratory-insertion partner.
Catalyst architecture and reaction environments actively govern reaction pathways and selectivities, providing divergent synthetic access to spirocyclic, fused, and polycyclic frameworks.
Existing methodologies exhibit uneven substrate scope and systematically lack quantitative metrics on catalyst efficiency, energy consumption, and material demand.