| Chalcone,a simple but unique structural unit,is widely embedded in pharmaceuticals and natural products.Consequently,a growing number of synthetic methodologies and broad biological investigations of chalcones have been reported.Surprisingly,the related studies of complex ?-alkyl chalcones are still relatively rare because only few methods for their preparation have been developed.Only a few synthetic methodologies have the shortcomings of limited range of substrates,harsh reaction conditions and poor reaction selectivity,which to some extent limits the related research of ?-alkyl chalcone.In addition,C-H activation has become a routine to construct complex molecules.Among them,transition metal-catalyzed C-H functionalization using directing groups has attracted great attention of researchers.Among them,oxidizing directing groups have attracted our attention,because the catalysts can be recycled by using the oxidation of the guiding groups,even if the additional oxidants aren't needed to add additional oxidants in the reaction system,which meets the demands of green chemistry.Therefore,it is feasible and significant to synthesize ?-alkyl chalcone by C-H functionalization based on the special properties of oxidation-oriented groups.The main contents of this paper include:By using N-phenoxyacetamides as substrates and using nonterminal propargyl alcohols as the coupling partners,we have developed an efficient rhodium-catalyzed redox-neutral C-H functionalization for accessing series of potentially bioactive ?-alkyl 2-hydroxychalcones.The reaction was carried out under simple and mild conditions.Using this synthetic methodology,we synthesized ?-substituted 5-fluoro-2-hydroxychalcones with potential anticancer activity.At the same time,the gram scale-up reaction have been realized.In addition,triazole and chromene derivatives were synthesized by derivatization.Finally,we carried out a simple exploration of the mechanism and proposed a possible mechanism. |
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