(S)-2-(4-Fluorophenyl)pyrrolidine is a chiral pyrrolidine derivative featuring a 4-fluorophenyl substituent at the 2-position. This compound serves as a crucial chiral building block and intermediate in pharmaceutical synthesis. Its primary and most significant application is in the research and development of central nervous system (CNS) drugs. It is a key intermediate in the synthesis of PF-04457845, a potent and selective fatty acid amide hydrolase (FAAH) inhibitor investigated for the treatment of pain and anxiety disorders. The (S)-enantiomer is specifically required for constructing the active pharmaceutical ingredient (API) with the desired pharmacological profile. The molecule combines a privileged pyrrolidine scaffold, common in bioactive molecules, with a fluorinated aromatic ring, which often enhances metabolic stability and binding affinity. Its synthesis and use are of high interest in medicinal chemistry for creating novel therapeutic agents targeting neurological conditions.