An efficient and user-friendly strategy for the synthesis of cyclopropane and dihydrofuran rings from difunctional compounds

K2CO3-NaHCO3-mediated conjugate-addition-initiated ring-closure (CAIRC) reaction of various active methylene compounds to 2-bromo-2-cyclopentenone in the presence of [BMIM]PF6-H2O (2:1) producing carbocyclic and heterocyclic compounds is described. The use of [BMIM]PF6-H2O as a solvent for CAIRC reaction is advantageous offering simple product isolation and shorter reaction times compared to conventional solvents. This reaction system can provide a general and practical method for the construction of 2,2-disubstituted cyclopropanes and polycyclic dihydrofuran derivatives containing electron-deficient substituents.