PREPARATION OF 3,3-DIARYLOXINDOLES BY SUPERACID-INDUCED CONDENSATIONSOF ISATINS AND AROMATICS WITH A COMBINATORIAL APPROACH

3,3-Diaryloxidoles are prepared in high yields (62-99%) by reaction of isatin or substituted isatins with aromatics in triflic acid. The rea ction shows a significant dependence on acid strength which suggests t he formation of diprotonated, superelectrophilic intermediates. Reacti on of isatin, benzene, and acid systems of varying strength (composed of CF3SO3H and CF3CO2H) showed that the acid strength must be more aci dic than H-0 = -11.5 for complete conversion to product. Reaction of i satins with mixtures of aromatics allows for the preparation of librar ies of 3,3-diaryloxindole products by combinatorial synthesis.