Synthesis of o‑Carborane-Fused Pyrazoles through Sequential C–N Bond Formation

Transition-metal-free synthetic method for o-carborane-fused pyrazoles as a new scaffold has been developed from the reaction of B(4)-acylmethyl or B­(3,5)-diacylmethyl o-carborane with 2-azido-1,3-dimethyl­imidazolinium hexafluorophosphate (ADMP) in the presence of DBU in acetonitrile through sequential diazotization and cyclization reaction in one pot, consequently allowing twofold C–N bond formation under extremely mild conditions and high functional group tolerance.