Zwitterionische Imidazolium- und Phosphonium-Derivate der Methylenmeldrumsäure [1,2] / Zwitterionic Imidazolium and Phosphonium Derivatives of Methylene-Meldrum’s Acid [1,2]

Abstract

2,2-Dimethyl-4,6-dioxo-5-pyridinomethyl-1,3-dioxan-5-yl-pyridinium ylide (9) reacts with 2,3-dihydro- 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1; R1 = iPr, R2 = Me) to give the zwitterionic imidazolium derivative 2,2-dimethyl-4,6-dioxo-5-(1,3-diisopropyl-4,5-dimethylimidazoliomethyl)- 1,3-dioxan-5-yl-imidazolium ylide (4) in good yield. Similarly, the phosphonium compound 2,2-dimethyl-4,6-dioxo-5-triphenylphosphoniomethyl-1,3-dioxan-5-yl-phosphonium ylide (5) is obtained from 9 and PPh3. The crystal structures of 4 and 5 are reported