Used in pharmaceutical synthesis as a protected building block for peptidomimetics and bioactive compounds. The Boc-protected pyrrolidine ring provides structural rigidity, while the ethynyl group allows further functionalization via click chemistry, especially in coupling reactions like Sonogashira or CuAAC. Commonly employed in the development of protease inhibitors and central nervous system agents due to its favorable conformational properties and ease of modification. Also utilized in combinatorial chemistry for generating diverse compound libraries.