《Tab.3 Substrate scope》

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《"串联反应合成2-氨基-3,5-二氰基-4H-吡喃衍生物（英文）"》

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With the optimized conditions in hand，we extended the substrate scope to a number of cyanochalcone derivatives.Differently substituted cyanochalcones afforded the 2-amino-3，5-dicyano-4H-pyran products in good to excellent yields（Tab.3 and Fig.3）.In the case of the non-substitued cyanochalcone，the yield was 99%（Entry 1）.Para-substitution provided better yields compared to ortho-substitution（Entries 4～5 and Entries 7～8，respectively），indicating that steric hindrance plays a role in the reaction.When the substituent was a p-dimethylamino group，the highest yield（99.6%）was obtained（Entry 9）.As for the electronic characteristics of the substituents，cyanochalcones bearing electron-withdrawing substituents generally gave excellent yields（Entries 2～5）.However，the electronic effect of electron-donating substituents was inconsistent.While p-dimethylamino cyanochalcone afforded near quantitative yield，the reaction efficiency of methoxy-substituted cyanochalcones diminished to 85.3%and 80.4%（Entries 7～8）.