Synthesis and Reactivity of the Phosphorus Analogues of Cyclopentadienone, Tricyclopentanone, and Housene

The phosphorus analogues of cyclopentadienone, tricyclopentanone, and housene were accessed from bis(cyclopropenyl)diphosphetanedione 3 , which was prepared by mixing 1,2,3‐tris‐tert‐butylcyclopropenium tetrafluoroborate ( 1 ) and sodium phosphaethynolate [Na(OCP)(dioxane)n]. While photolysis of 3 results in decarbonylation, yielding bis(cyclopropenyl)diphosphene 4 and after rearrangement diphosphahousene 5 , thermolysis of 3 leads to phosphatricyclo[2.1.0.0]pentanone 7 . Metal‐mediated valence isomerization of 7 and subsequent demetalation provides access to phosphacyclopentadienone 12