Assembly of trifluoromethylated fused tricyclic pyrazoles cyclization of β-amino cyclic ketones.

Fused polycyclic pyrazoles are an important class of heterocyclic compounds; thus, the development of efficient methods for their preparation becomes highly urgent. Herein, we reported an efficient method for the synthesis of trifluoromethylated fused tricyclic pyrazoles intramolecular cyclization of cyclic ketone-derived amines. Mechanistic studies provide evidence for the generation of trifluoromethylated β-diazo ketones as intermediates diazotization with the use of -butyl nitrite. The synthetic utility of this method is highlighted by scale-up synthesis and the derivatization of the obtained fused tricyclic pyrazole products.