Phosphine-Mediated 2+1 Cyclization of Coumarins for the Efficient Construction of cyclopropaccoumarin Scaffolds

Key Points

• This research explores the efficient synthesis of cyclopropa[c]coumarin scaffolds using phosphine-mediated reactions.
• Phosphine-mediated [2+1] annulation of coumarins with α-keto esters or isatins
• Utilization of in situ-generated K-R adducts as intermediates
• Successfully accessed cyclopropa[c]coumarin cores and spirooxindole-fused variants
• Demonstrated efficiency in scaffold construction with the proposed method