Indole must be hydrogenated into indoline, and then indoline would be cracked into aniline and ammonia quickly.
Synthesis of 1-Boc-5-fluoro-spiro-(indoline-3,4'-piperidine) hydrochloride
Synthesis of 1'-Boc-5-fluoro-spiro-(indoline-3,4'-piperidine)
Synthesis of 1,3,3,5-tetramethyl-6-nitro-indoline spiroben-zopyrans