Abstract An unreported 5-endo-trig atom-transfer radical cyclization of cyclic N-α- dichloroacyl-ketene-N, S-acetals, which evolves as a tandem radical-polar process, is described. The reaction, which is carried out in the presence of a Cu (I) complex catalyst (10 mol%) and an inorganic base (ie, carbonate), can be exploited as the key step for a novel, short, and versatile synthesis of the 3, 4-disubstituted maleic anhydride nucleus.
[Mahidol, Chulabhorn; Pinyopronpanit, Yongyut; Radviroongit, Shuleewan; Thebtaranonth, Chachanat; Thebtaranonth, Yodhathai Journal of the Chemical Society, Chemical Communications, 1988 , # 20 p. 1382 - 1383]
![1-{3-[(7-ethyl-8-methyl-6-oxo-3,4-dihydro-2H-pyrrolo[2,1-b][1,3]thiazin-6(8aH)-yl)sulfanyl]propyl}-3-ethyl-4-methyl-1H-pyrrole-2,5-dione Structure](https://image.chemsrc.com/caspic/225/1191077-89-0.png)
