The Reactions of Nitrones with Indoles

The reaction of nitrones with various indole derivatives has been studied. When the reaction was promoted by ClSiMe3, the isolated products were 3,3′-diindolylalkanes. With HCl as the activating reagent, 3-indolylhydroxylamines were isolated. The diastereoselectivity of this condensation with a nitrone derived from cysteine was investigated. A method for the introduction of an alkylhydroxylamino group onto position 2 of indole, the synthesis of three natural 3,3′-diindolylalkanes and of non-symmetric diindolylalkanes are also reported.