Visible-light-induced Synthesis Of Isoquinolion-1-ol Derivatives

In recent years,nitrogen-containing aromatic heterocycle is one of the hot spots in synthetic chemistry.Nitrogen heterocyclic isoquinoline derivatives are widely distributed in natural products and drug molecules and are a kind of common organic molecular framework.Isoquinoline derivatives have important application value in biological active molecules,organic synthesis intermediates,organic catalysis,agricultural chemistry,medicine,organic materials and other fields.Therefore,many scientists have studied the synthesis of isoquinoline,so far,the synthesis of isoquinoline,need to be catalyzed by precious metal,and can be carried out at a higher temperature,reaction conditions are more stringent.Therefore,the synthesis of isoquinoline derivatives by mild conditions,simple steps and cheap substrates has important research significance.In this paper,a new synthesis method of isoquinoline,using n-benzamide-2,4,6-triphenylpyridine salt and alkyne as reaction substrates,was studied.N-benzamide-2,4,6-triphenyl pyridine salt has strong oxidation property,which makes it undergo oxidation quenching with the excited photocatalyst,and produces benzamide radical.In this way,the benzamide radical and the aromatic alkyne radical are added to synthesize the target product,and the photocatalyst is reduced by the intermediate to form a photocatalytic redox cycle.Eosin is used as photocatalyst,which does not need precious metal catalyst.The method is mild and environmentally friendly,and conforms to the principle of atomic economy and the concept of green chemical industry.A series of isoquinoline derivatives?40-80%yield?were prepared by this strategy.Finally,the mechanism was verified by mechanism verification experiment.The condition of photocatalysis reaction is mild condition and room temperture.Using the eosin Y as the catalysis reduce the response cost.The 2,4,6-triphenylpyridiniums and alkynes are common chemical substrate and don't need further compound.Except the NaBF₄,there isn't other additive,which conform to green economy principle.