Three-Component Reaction between Triphenylphosphine, Dialkyl Acetylenedicarboxylates and 3-(3,5-Dimethyl Pyrazol-1-yl)-3-oxo Propionitrile

Abstract

Protonation of the reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine by 3-(3,5-dimethyl pyrazol-1-yl)-3-oxopropionitrile leads to vinylphosphonium salts which undergo Michael addition with the conjugate base of the CH-acid to produce highly functionalised, salt-free phosphorus ylides in excellent yields.

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

“…The generation of two isomers of phosphorus ylides was carried out via the addition of triphenylphosphine to DAAD (dialkyl acetylenedicarboxylate), followed by protonation of the intermediate adduct 75 by 3-(3,5-dimethylpyrazol-1-yl)-3-oxopropanenitrile ( 76 ) as a CH-acid. The expected resonance-stabilized ylides 77 were obtained in high yields of 90–95% ( Scheme 48 ) [ 65 ].…”