Construction Of Dihydrobenzofurans Based On1,3-Dicarbonyl Compounds

Dihydrobenzofurans are common structural subunits in many natural isolates and pharmacological agents. Many of them are biologically active molecules and also serve as versatile building blocks in organic synthesis. This dissertation reviewed the research progress of dihydrobenzofurans, and then pay attention to construction dihydrobenzofurans based on1,3-dicarbonyl compounds, The results and details are shown below:The efficient methods to synthetize dihydrobenzofurans from1,3-dicarbonyl compounds are described in this thesis. The K2CO3-promoted 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) and2-halo-1,3-dicarbonyl compounds (diethyl a-bromomalonate, diethyl a-chloromalonate, ethyl2-chloroacetoacetate, and3-chloro-pentane-2,4-dione) were carried out to provide a series of functionalized dihydrobenzofurans in moderate to excellent yields (37%-97%). Experiments show that the applicable scope of substrates are very extensive. The structure of the substituted dihydrobenzofurans were confirmed by the single-crystal X-ray analysis.Multicomponent one pot reactions to construct complex molecules is simple to operate, reduce the pollution of the environment, improve atom-and step-economy. The DBU-promoted multicomponent cascade reactions (mannich alkylation, aldol alkylation) of salicylic aldehyde derivatives (2-hydroxyarylimines, salicylic aldehydes) and1,3-dicarbonyl compounds (diethyl malonate, ethyl acetoacetate and diethyl malonate) were carried out to provide a series of functionalized dihydrobenzofurans in moderate to excellent yields (44%-81%). Experiments show that the applicable scope of substrates are very extensive.