(R)-3-Methoxypyrrolidine is a chiral, non-natural heterocyclic amine characterized by a pyrrolidine ring substituted with a methoxy group at the 3-position. It is a clear, colorless to pale yellow liquid and serves as a versatile chiral building block in organic synthesis. This compound is primarily employed as a key intermediate in the pharmaceutical industry for the synthesis of active pharmaceutical ingredients (APIs). Its chiral pyrrolidine scaffold is a privileged structure found in numerous bioactive molecules. A prominent application is its use in the synthesis of JAK (Janus kinase) inhibitors, such as Tofacitinib and its analogs, where it contributes to the core structure and influences the stereochemistry critical for biological activity. It is also utilized in the development of other therapeutic agents targeting various diseases. As a chiral amine, (R)-3-Methoxypyrrolidine is a valuable synthon in asymmetric synthesis and medicinal chemistry. It is commercially available in high enantiomeric purity, underscoring its importance in the production of enantiomerically pure drugs. Standard safety precautions for handling amines and flammable liquids should be observed.