Boc-L-Phe(4-NH-Poc)-OH is a chemical reagent with an azido group used in peptide synthesis as a protected orthogonal building block. The propargyl group, commonly abbreviated as Poc or Pryoc, serves as a standard alkyne component for click conjugation and can be combined with tetrazine connectors in copper-free Diels-Alder type click reactions. It also acts as a special protective group for amines, hydroxyls, and esters, stable under neat TFA but can undergo TFA:DCM cleavage with Co2(CO)8 at room temperature. Deprotection reports with other transition metals such as palladium exist. Additionally, Boc-L-Phe(4-NH-Poc)-OH contains an Alkyne group that reacts with azide-containing molecules via copper-catalyzed azide-alkyne cycloaddition (CuAAC).