A quantum chemical study on the reaction of 1-aryl-1,2-dihydrophosphinine oxides with dimethyl acetylenedicarboxylate

The reaction of cyclic phosphine oxides (1) and dialkyl acetylenedicarboxylate giving the corresponding β-oxophosphorane/ylide (2) was studied by quantum chemical calculations. Relative energies of the transition states (6 and 7), intermediates (32) and possible products, such as oxophosphorane/ylide 2 or Diels Alder cycloadducts 5 were calculated for the potential pathways. Geometry of a few relevant species (2a*, 3a2∗, 6 and 7) was also evaluated.