Strain‐release transformations of bicyclo1.1.0butanes are powerful methods for constructing four‐membered rings and bicyclon.1.1alkane scaffolds of medicinal interest. However, the lack of efficient methods for the synthesis of bridgehead‐heterocycle‐substituted bicyclo1.1.0butanes limits their application in the synthesis of corresponding heterocycles. Herein, we disclose alkynylbicyclo1.1.0butanes (ABCBs) as versatile synthons: the strained bicyclobutane core remains unscathed while the alkyne handle undergoes mild, late‐stage cycloadditions to deliver triazole‐, isoxazole‐, free‐NH‐pyrrole, free‐NH‐pyrazole or silacyclohexene‐decorated BCBs that are otherwise difficult to access by conventional routes.
Li et al. (Wed,) studied this question.