Metal-Free Radical Haloazidation of Benzene-Tethered 1,7-Enynes Leading to Polyfunctionalized 3,4-Dihydroquinolin-2(1H)-ones

Ai-Fang Wang#, Yi-Long Zhu#, Shu-Liang Wang*, Wen-Juan Hao, Guigen Li, Shu-Jiang Tu,* Bo Jiang*

(#为共同一作)

A new cascade three-component haloazidation of benzene-tethered 1,7-enynes for the formation of biologically interestingazidylated 3,4-dihydroquinolin-2(1H)-ones has been achieved under mild and metal-free conditions using TMSN₃ as a N₃ source and NIS (or NBS, or NCS) as a halogen source.The reaction pathway involves in situ-generated azidyl radical-triggered a,b-conjugated addition / 6-exo-dig cyclization / radical coupling sequence, resulting in the successive multiple bond-forming eventsincluding carbon–nitrogen,carbon–carbon andcarbon–halogen bonds to rapidly construct complex heterocyclic molecules. Furthermore, the resultant products would be useful building blocks in discovery of lead compounds and other biologically interesting N₃-containing heterocycles

 J. Org.  Chem. 2016, 81, 1099-1105