3.3- Disubstituted oxindoles, formation

NHCH2), which exhibits a typical dihydroindole UV-spectrum, and which, in contrast to mitraphylline, couples with diazotized sulfanilic acid. The formation of a dihydroindole derivative, and not an indole derivative, in this reduction is an indication, though not perhaps a conclusive one, that the molecule is a 3,3-disubstituted oxindole hence, structure V is invalidated (57). 

The selective oxidative aromatic C-H bond functionalisation for new carbon-carbon bond formation is versatile, and various copper-catalysed or mediated reactions have been developed under molecular mg gen or air. For intramolecular reactions, 3,3-disubstituted oxindoles are provided by the oxidative coupling of Ar-H and C-H moieties in the presence of stoichiometric amounts of copper(ii) complex and a base (Scheme 15.51). Similar reactions are carried out catalytically with copper(ii) acetate (5 mol%) under air (Scheme 15.52). Indoline-2,3-diones (isatins) are afforded by... 

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