Boc-NH-PEG2-C2-NH2 is a PROTAC linker, which refers to the alkyl/ether composition. Boc-NH-PEG2-C2-NH2 can be used in the synthesis of a series of PROTACs. Boc-NH-PEG2-C2-NH2 is a PEG derivative containing an amino group and Boc-protected amino group. The amino group is reactive with carboxylic acids, activated NHS esters, carbonyls (ketone, aldehyde) etc. PEG Linkers may be useful in the development of antibody drug conjugates and PROTACs.