A Rearrangement in the λ⁵‐Phosphorin Series Analogous to the Claisen Rearrangement

Polycyclic carbon-phosphorus heterocycles

“…An interesting rearrangement was observed by heating 267 in toluene which gave 268 via [3,3]sigmatropic rearrangement. 301 Upon extended heating of 267, a crystalline product was obtained for which the tentative structure 269 was suggested. The latter was indicated as being examined by x-ray analysis, and the structure must therefore be considered tentative.…”