Preliminary Investigation of the [3+2] Cycloaddition Reactions of 2-Alkylidenephosphiranes

The 2-alkylidenephosphirane complex 1 reacts with norbornene and dimethyl acetylenedicarboxylate at 100 °C in toluene to give the corresponding [3+2] cycloadducts. With norbornene, only the P−C distal bond is involved, whereas with acetylenedicarboxylate, both the P−C distal and proximal bonds react.