Cascade One-Pot Synthesis of Indanone-Fused Cyclopentanes from the Reaction of Donor-Acceptor Cyclopropanes and Enynals via a Sequential Hydrolysis/Knoevenagel Condensation/[3+2] Cycloaddition

A cascade reaction of donor-acceptor cyclopropanes with enynals to construct indanone-fused cyclopentanes via a sequential hydrolysis/Knoevenagel condensation/[3+2] cycloaddition is reported. The desired indanone-fused cyclopentanes were obtained in good yields. This method features mild reaction conditions and broad substrate scope, which render it very appealing to chemists for the synthesis of complex molecules containing an indanone-fused cyclopentane moiety. Moreover, the products could be further converted into compounds with different functional groups through the well-known transformations.