Ethyl 3-iodobicyclo[1.1.1]pentane-1-carboxylate is used as a key intermediate in medicinal chemistry for the synthesis of bioisosteres, particularly in place of phenyl or tert-butyl groups to improve metabolic stability and solubility in drug candidates. Its strained bicyclic structure enables unique three-dimensional scaffolding, enhancing binding selectivity in pharmaceuticals. The iodine substituent at the 3-position facilitates cross-coupling reactions, such as Suzuki-Miyaura or Negishi couplings, to introduce the bicyclo[1.1.1]pentane moiety into complex molecules. The ethyl carboxylate group at the 1-position provides a versatile handle for further derivatization. Commonly employed in fragment-based drug discovery and in the development of CNS-targeted compounds due to favorable physicochemical properties.