Hexafluoroisopropanol: a powerful solvent for the hydrogenation of indole derivatives. Selective access to tetrahydroindoles or cis-fused octahydroindoles.

Pd/C in HFIP was used to hydrogenate indole derivatives under relatively mild conditions, leading to potential synthetic intermediates of bioactive compounds. Depending on their substitution, tetrahydroindoles or octahydroindoles could selectively be obtained.