Synthesis 2025; 57(02): 425-440
DOI: 10.1055/a-2382-9631
paper
Special Topic Dedicated to Prof. H. Ila

PIFA-Mediated Intramolecular Dearomatization of Phenol-Tethered 1,2-Diazoles: Synthesis of Spirocyclohexadienone-pyrazolo[3,4-b]piperidinones

Pradeep Natarajan
,
Pratibha Bachhaley
,
Sweta Tripathy
,
Ashok Vasantharaj P
,
Saravanan Peruncheralathan
This work was supported by the Department of Atomic Energy, Government of India.


Abstract

In recent years, the significance of spirocyclic motifs in drug discovery has increased, owing to their unique ability to engage biological targets. We present the first example of PIFA-mediated dearomative spirocyclization of phenol-tethered pyrazoles, highlighting intramolecular trapping by the pyrazole moiety. This method efficiently affords a variety of spirocyclohexadienone-pyrazolo[3,4-b]piperidinones with yields of up to 82%. Mechanistic studies reveal that the dearomatization process involves a cationic intermediate.

Supporting Information



Publication History

Received: 17 June 2024

Accepted after revision: 08 August 2024

Accepted Manuscript online:
08 August 2024

Article published online:
12 September 2024

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