Synthesis of Pyrazolines via (3+2) Cycloaddition of Nitrile Imines and N-Silyl Enamines

Abstract

The synthesis of tricyclic fused pyrazolines from N-silyl enamines and nitrile imines is presented. N-Silyl enamines are an emerging class of enamines that can be used as free enamine surrogates. The N-silyl enamines, prepared from readily available isoquinolines, underwent (3+2) cycloaddition with a wide range of nitrile imines to form the corresponding pyrazolines in moderate to good yields. This cascade protocol entailed the in situ utilization of both N-silyl enamine and nitrile imine intermediates.

Key words

N-silyl enamines - B(C₆F₅)₃ - (3+2) cycloaddition - pyrazolines - nitrile imines

Publication History

Received: 28 February 2025

Accepted after revision: 10 April 2025

Accepted Manuscript online:
10 April 2025

Article published online:
08 May 2025

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