A direct C-H/Ar-H coupling approach to oxindoles, thio-oxindoles, 3,4-dihydro-1 H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines.

A copper(II)-catalysed approach to oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines via formal C-H, Ar-H coupling is described. In a new variant, copper(II) 2-ethylhexanoate has been identified as an inexpensive and efficient catalyst for this transformation, which utilises atmospheric oxygen as the re-oxidant.

Copper-mediated construction of spirocyclic bis-oxindoles via a double C-H, Ar-H coupling process.

A double C-H, Ar-H coupling process for the conversion of bis-anilides into spirocyclic bis-oxindoles, enabling the concomitant formation of two all-carbon quaternary centers at oxindole 3-positions in a diastereoselective manner, is described. The optimum cyclization conditions utilize stoichiometric Cu(OAc)2·H2O/KOtBu in DMF at 110 °C and have been applied to prepare a range of structurally diverse bis-spirooxindoles in fair to good yields (28-77%); the method has also been extended to prepare bis-oxindoles linked by a functionalized acyclic carbon chain.