Four-Component Synthesis of Dialkyl 2-(1,3-Dioxo-1,3-dihydro-2H-inden-2-yliden)-3-(2,2,2-trifluoroethoxy)succinates from Triphenylphosphine, Acetylenic Esters, 2,2,2-Trifluoroethanol, and Ninhydrin

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by 2,2,2-trifluoroethanol, leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce the corresponding fluorine-containing stabilized phosphorus ylides. Intermolecular Wittig reaction of the fluorine-containing stabilized phosphorus ylides with ninhydrin leads to the corresponding highly electron-poor fluorine-containing alkenes.

Keywords:

• 2,2,2-trifluoroethanol
• acetylenic ester
• intermolecular Wittig reaction
• ninhydrin
• triphenylphosphine

Acknowledgments

This work was supported by the Zanjan Islamic Azad University Research Council via research project number ZIAURC82.13882. We also thank Dr Mehdi Rahnema (Rector of Zanjan Islamic Azad University Research Council) for helpful discussions and financial support.