A Direct C-H/Ar-H Coupling Approach to Oxindoles, Thio-oxindoles, 3,4-Dihydro-1H-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.