2-(tert-Butoxy)-2-oxoacetic acid, also known as tert-Butyl 2-oxoacetate or tert-Butyl glyoxylate, is a versatile organic building block. Its structure features a reactive glyoxylate moiety (an α-ketoester) protected by a tert-butyl group, which provides stability and influences its reactivity profile. This compound is primarily employed as a key intermediate in organic synthesis. The tert-butyl ester group serves as a common protecting group for carboxylic acids, making this reagent valuable in multi-step syntheses where selective deprotection is required. Its α-ketoester functionality makes it a useful electrophile in various carbon-carbon bond-forming reactions, such as aldol-type additions and nucleophilic substitutions, for the synthesis of α-hydroxy acids, amino acids, and other complex molecules. While not typically a final product, its utility lies in its role as a protected form of glyoxylic acid, facilitating the controlled introduction of the glyoxylate unit into target structures in medicinal chemistry and materials science research.