Synthetic route to 4‐(2‐aminoethyl)‐5‐hydroxyindole derivatives

Abstract

Abstract In synthetic studies leading to the title compounds, application of the Claisen rearrangement of 5‐allyloxyindole was investigated. Almost quantitative yields of Claisen rearrangement product were realized, and a strategy for oxidative cleavage of the allyl double bond to an indole‐4‐acetaldehyde derivative was developed. A new method for conversion of 2,3‐dihydroindoles into indoles was utilized: air oxidation in a strongly basic environment. The Claisen rearrangement of allyloxyindoles is presented as a method having considerable potential utility in synthesis of a variety of polysubstituted indoles.