Reaction of 5,6-difluoroisatin (I) with sodium methanethiolate affords thioether (II). Subsequent reduction of isatin (II) with LiAlH4 provides 5-fluoro-6-methylsulfanylindole (III). Alkylation of indole (III) with (S)-2-(t-butoxycarbonylamino)propyl methanesulfonate (IV) in the presence of KOH in DMSO leads to the N-alkylated indole (V), which is further reduced to the corresponding indoline (VI) by means of NaBH3CN in AcOH. The N-Boc protecting group of (VI) is finally removed by treatment with trifluoroacetic acid in CH2Cl2 (1,2).