Tilivalline 1, a metabolite from Klebsiella pneumoniae var. ocytoca, was easily synthesized in five steps from (S)-proline and 3-(benzyloxy)isatoic anhydride 4g. This synthesis is based on modified Curtius reactions of 3-substituted phthalic anhydrides 11 to 3-substituted isatoic anhydrides 4, conversion of lactams 6 to the acyliminium precursors 7 and stereoselective introduction of indole from the less hindered side of 7.