This compound, 4-((tert-Butyldimethylsilyl)oxy)but-2-ynoic acid, is a specialized intermediate in organic synthesis. It features a hydroxyl group protected as a tert-butyldimethylsilyl (TBDMS) ether at the 4-position, which shields it during reactions involving the carboxylic acid or the terminal alkyne. The alkyne moiety enables efficient participation in click chemistry, such as azide-alkyne cycloadditions, for building complex structures. This makes it valuable for the synthesis of pharmaceuticals, natural products, bioactive compounds, and advanced materials, where selective protection and modular assembly are essential.