Synthesis of C‑Allenyl o‑Carboranes through Copper(I)-Catalyzed Coupling Reaction of Ethynyl o‑Carboranes with N‑Tosylhydrazones

A synthetic
method for C-allenyl o-carboranes
was demonstrated using the coupling reaction of ethynyl o-carboranes with N-tosylhydrazones under
copper(I) catalysis. This approach is significant because it achieved
high yields despite the incorporation of carboranes with various substituents.
Moreover, this work is notable in that it successfully synthesized
not only disubstituted allenes but also trisubstituted allenes.