Efficient preparation of (S)‐2‐(3,5‐dimethylphenyl)pyrrolidine via a recycle process of resolution

(S)‐2‐(3,5‐dimethylphenyl)pyrrolidine((S)‐1), a key intermediate in the synthesis of aticaprant, was effectively prepared via a recycle process of resolution/racemization. The desired (S)‐1 was obtained by resolution of its racemate with D‐tartaric acid and some alkaline conditions were screened to racemize the undesired (R)‐1 in the resolution mother liquor, and the best (in DMSO with KOH) was identified. Finally, the desired freebase (S)‐1 was obtained in a yield of 63.6% with excellent enantioselectivity (98.7% ee) after three times of recycle process. The desired freebase (S)‐1 was obtained in a yield of 63.6% with excellent enantioselectivity (98.7% ee) after three times of recycle process.