| Sumario: | Direct and efficient catalytic reactions with excellent regioselectivity for the preparation of a series of substituted isoindoles, isoquinolines, and imidazoles are reported. Reaction of CH(2-CN)C≡C-R with an array of amines, catalyzed by 10 mol % of [ó:η:η-(OCH)(MeNCH)CBH]Ti(NMe) (1), gives a series of substituted isoindoles in very high yields. In a similar manner, interaction of CH(2-CHCN)C≡C-Ph with various kinds of amines affords a wide range of substituted isoquinolines. On the other hand, treatment of propargylamines (R'C≡CCHNHR") with nitriles in the presence of 10 mol % of 1 produces a class of substituted imidazoles in high yields. A possible reaction mechanism is proposed, involving sequential inter- and intramolecular C-N bond formation via hydroamination/cyclization reaction of cyanoalkynes with amines or nitriles with propargylamines catalyzed by titanium amides.
|
|---|