DBCO (dibenzocyclooctyne), also known as ADIBO (azadibenzocyclooctyne) or DIBAC (dibenzoazacyclooctyne), is increasingly used as click reactant in copper-free click chemistry. In many reaction environments (in vitro and in vivo), DBCO reacts rapidly and selectively with azides forming the corresponding triazole compounds. Due to the unfavorable ring strain in the cyclooctyne ring of the DBCO, the reaction is greatly facilitated and can thus proceed spontaneously without a metal catalyst.

The copper-free DBCO-azide click chemistry is a good orthogonal strategy compared to conventional coupling reactions, and thus allowing selective multiple labeling of biomolecules.

Using copper-free click reactions, there are various cyclooctyne derivatives differing greatly in terms of their reaction kinetics and hydrophilic properties. In addition to DBCO, biomers.net also offers SCO-PEG3 (Strained Cyclooctyne) as another representative of cyclooctynes.