Iodo-carbocyclization of electron-deficient alkenes: synthesis of oxindoles and spirooxindoles.

Cyclisative carbo-iodination of N-alkyl-N-arylacrylamide derivatives (3) in the presence of PhI(OAc)(2)/I(2) afforded functionalized 3-(iodomethyl)-3-substituted-indolin-2-ones (4) in good to excellent yields. With a suitably functionalized linear amide, spirooxindole 8 was prepared in a one-pot fashion via a sequence of iodo-arylation followed by an in situ base-promoted intramolecular S(N)2 reaction.