Boc-aminooxy-PEG1-propargyl

Boc-aminooxy-PEG1-propargyl is a PROTAC linker building block designed to connect an aminooxy-containing handle with a terminal propargyl functionality, enabling modular assembly of targeted protein degraders. Its PEG-based spacer supports solubility and conformational flexibility at the linker level, while the Boc-protected aminooxy group provides controlled deprotection and subsequent coupling. The molecule is well suited for researchers constructing PROTACs via orthogonal chemistries, with the detailed structural and synthetic considerations provided below.

Structure: The linker contains a Boc-protected aminooxy moiety connected through a short polyethylene glycol spacer to a propargyl (terminal alkyne) group. It features an ether linkage within the PEG segment, a carbamate from Boc protection, and a carbon–carbon triple bond at the propargyl terminus. These functional groups support orthogonal conjugation strategies.

Reactivity: PROTAC assembly using this linker typically relies on orthogonal reactions that preserve the terminal alkyne for later bioconjugation while enabling aminooxy activation or deprotection when needed. Boc removal is commonly performed under mild acidic conditions to reveal the aminooxy functionality, which can then participate in oxime-forming ligations with carbonyl partners. The terminal alkyne can be used in copper-catalyzed or strain-promoted azide–alkyne cycloaddition, depending on the PROTAC design and available partners.