Selective strain-promoted azide-alkyne cycloadditions through transient protection of bicyclo[6.1.0]nonynes with silver or gold

Complexation of bicyclo[6.1.0]nonynes with a cationic silver or gold salt results in protection from a click reaction with azides. The cycloalkyne protection using the silver or gold salt enables selective strain-promoted azide-alkyne cycloadditions of diynes keeping the bicyclo[6.1.0]nonyne moiety unreacted. Complexation of bicyclo[6.1.0]nonynes (BCNs) with silver or gold results in protection from a click reaction with azides. The protection enables selective strain-promoted azide-alkyne cycloadditions of diynes keeping the BCN moiety unreacted.