(R)-1-Boc-3-ethynylpyrrolidine is a chiral building block featuring a pyrrolidine ring substituted with a Boc-protected amine and an ethynyl group at the 3-position. Its molecular formula is C11H17NO2, and it is typically supplied as a colorless to pale yellow liquid or low-melting solid. The presence of both a protected amine and an alkyne handle makes it a versatile intermediate for further functionalization through reactions such as Sonogashira coupling or click chemistry. This compound is primarily utilized in medicinal chemistry as a key chiral intermediate for the synthesis of bioactive molecules. Its most notable application is in the development of pharmaceutical candidates, particularly as a precursor for KRAS G12C inhibitors, such as sotorasib (AMG 510) and adagrasib (MRTX849). The chiral pyrrolidine scaffold is integral to binding the target protein, and the ethynyl group serves as a crucial point for attachment to other molecular fragments. Due to its high value in targeted cancer therapy research, (R)-1-Boc-3-ethynylpyrrolidine is a specialty chemical of significant interest in drug discovery pipelines. It should be stored under inert conditions at low temperatures to maintain stability. Handling requires standard precautions for laboratory chemicals.