Metal-Catalyzed Radical Tandem Cyclization:Synthesis Of Nitrogen/Oxygen-Containing Heterocycles

Heterocyclic compounds are the largest class of organic compounds,accounting for approximately one-third of it is widely found in many natural products,medicines,pesticides and other important chemical products.Oxygen-and nitrogen-containing heterocyclic compounds are its important branches The radical tandem cyclization has high atom economy and step economy,and has a wide range of applications in the fields of chemistry and life sciences,and is often used in the synthesis of heterocyclic compounds.Radical acceptors with unsaturated bonds play a key role in realizing fast,concise,and efficient radical tandem cyclization reactions.In summary,we have synthesized a series of nitrogen-and oxygen-containing heterocyclic compounds using radical tandem cyclization reactions.The specific research contents are as follows:(1)A nickel-catalyzed cascade addition/cyclization of 2-azido-N-arylacrylamides and cyclobutanone oxime esters for the construction of 3-cyanoalkylated quinoxalin2(1H)-ones is developed.This reaction proceeds under mild conditions with good functional group tolerance and broad substrate scope.Preliminary mechanistic experiment indicated that the cyanoalkyl radical might be involved in this transformation.(2)A visible light photocatalyzed or metal-catalyzed three-component cyanoalkylsulfonylation of 1-(allyloxy)-2(1-arylvinyl)benzenes,potassium metabisulfite and cyclobutanone oxime esters is developed.The present reaction provides a direct approach to diverse cyanoalkylsulfonylated benzoxepines in moderate to good yields.This transformation displays a wide substate scope,wide functional group tolerance and potential for product derivatization.