AlCl3 Catalyzed Oxo-Diels-Alder and Wittig-Type Reaction of 2,3-Dimethyl-1,3-Butadiene With Acyl Phosphonates

Different aliphatic and aromatic acyl phosphonates were synthesized using Arbuzov reaction and subjected to Oxo-Diels-Alder (ODA) reaction with 2,3-dimethyl-1,3-butadiene at -78 °C. AlCl3 was found the best catalyst to obtain the desired ODA products from acyl phosphonates in only 30 minutes at low temperature, as compared to 100 °C - previously reported. The same reaction was repeated at room temperature but, instead of ODA, Wittig-type product was obtained. All the products were characterized by NMR spectroscopy and mass spectrometry. 1H,31P and 13C,31P couplings were observed in the NMR spectra.