Abstract
An efficient synthesis of stable phosphonate ylides and phosphonate esters is described via a one-pot reaction between activated acetylenes and triphenylphosphite in the presence of sulfonamides and heterocyclic NH-acids. Single X-ray diffraction analysis and NMR studies were used in characterizing the ylides and phosphonate ester products. Dynamic NMR studies performed on a phosphonate ylide allowed the calculation of the free energy barrier for the interconversion between the geometrical isomers (E) and (Z).
Keywords: Dialkyl acetylenedicarboxylates, sulfonamide NH-acids, heterocyclic NH-acids, triphenylphosphite, phosphonate ylide, dynamic NMR, IR, C NMR spectra, single crystal X-ray diffraction analysis, Heraeus CHN-O-Rapid analyzer, FINNIGAN-MATT, Shimadzu IR-460 spectrometer, BRUKER DRX-500 AVANCE, Oxford Diffraction Xcalibur-S CCD, X-Ray Crystallography, SHELX-97, 2-benzoxazolinone