Aggregative activation and heterocyclic chemistry I complex bases promoted arynic cyclisation of imines or enaminoketones; regiochemical synthesis of indoles
摘要:
The complex base NaNH2-t-BuONa allowed expeditious syntheses of indoles by arynic cyclisation of imines or enaminoketones prepared from halogeno anilines and carbonyl derivatives. Unstable imines may be used without purification, complex bases being unsensitive to impurities. It is showed that this kind of reaction may be applied to mixture of substrates suitably halogenated on the benzene ring. Formation of three components aggregates is proposed to explain a number of observations.
I2/DMSO-mediated substrate selective oxidation of tetrahydro indole-2,4-dione towards 4-hydroxy isatins and 5,6-dihydro-1H-indole-2,4-dione derivatives
indole-2,4-diones from readily available β-enaminones and glyoxal and subsequent I2/DMSO-mediated oxidation/aromatization of tetrahydro indole-2,4-dione to produce 4-hydroxyisatin derivatives. The key aspect of this protocol includes the dual catalytic activity of molecular iodine in the presence of DMSO. Mechanistic study suggested that this reaction is substrate selective as corresponding aromatization