K2CO3-promoted domino reactions: construction of functionalized 2,3-dihydrobenzofurans and clofibrate analogues.

The K(2)CO(3)-catalyzed domino reactions (Michael alkylation, Mannich alkylation, and aldol alkylation) of salicylic aldehyde derivatives (2-hydroxyaryl-α,β-unsaturated ketones, 2-hydroxyarylnitroalkenes, 2-hydroxyarylimines, and salicylic aldehydes) and 2-halo-1,3-dicarbonyl compounds (diethyl α-bromomalonate, diethyl α-chloromalonate, ethyl 2-chloroacetoacetate, and 3-chloropentane-2,4-dione) were carried out under mild conditions to provide a series of functionalized 2,3-dihydrobenzofurans in moderate to excellent yields. The novel transformations simultaneously gave a series of clofibrate analogues, which possess various substitution patterns.