Diphosphirenes as intermediates for phosphorus-carbon cage compounds

5 Diphosphirenes as Intermediates for Phosphorus-Carbon Cage Compounds 

When the aminophosphinidine complex 46 (R = = cyclohexyl) is generated by thermal 

A fairly obvious interpretation would involve the cleavage of the diphosphirene 47 (R = H, R = o-tolyl) to the carbene 49 and [3 + 2]-cycloaddition of the latter with a second equivalent of 9 a to furnish the triphosphole 51. The remaining two equivalents of phospha-alkyne are incorporated by Diels-Alder (- 52) and homo-Diels-Alder reactions (- 48), respectively [49]. 

---