(S)-alpha,alpha-Diphenyl-3-pyrrolidineacetamide, with CAS number 133099-11-3, is a chiral pyrrolidine derivative. It is a synthetic organic compound characterized by a pyrrolidine ring, a central amide linkage, and two phenyl groups attached to the alpha-carbon relative to the amide carbonyl. This specific stereochemistry (S-configuration) is crucial for its biological activity and interaction with target receptors. This compound is primarily known as a key intermediate in the synthesis of potent and selective neurokinin-1 (NK1) receptor antagonists. Its most prominent application is in the research and development of drugs targeting conditions like chemotherapy-induced nausea and vomiting (CINV), depression, and anxiety disorders. The structure serves as a core scaffold or a critical chiral building block for constructing more complex drug candidates that modulate the NK1 receptor pathway. As a specialized chiral intermediate with a defined pharmacological target, its use is almost exclusively within pharmaceutical research and development. It is not a commodity chemical or a general-purpose synthesis reagent. Handling requires standard laboratory safety precautions for organic compounds.