Used primarily in the synthesis of complex organic molecules, especially in pharmaceutical research. Its structure supports selective binding and functionalization, making it valuable in developing hormone-based therapeutics. Commonly employed as an intermediate in the preparation of steroidal compounds, particularly in the creation of modified estrogen derivatives for use in contraceptive agents and hormone replacement therapies. The ethynyl group enhances metabolic stability, allowing for improved bioavailability in final drug products. Also utilized in research settings for probing biological pathways involving nuclear receptors.