Unexpected Isomerization of Hexa‐tert‐butyl‐octaphosphane

Octaphosphane {cyclo‐(P(4) tBu(3))}(2) (1) undergoes an unexpected isomerization reaction to the constitutional isomer 2,2′,2′′,2′′′,3,3′‐hexa‐tert‐butyl‐bicyclo[3.3.0]octaphosphane (2) in the presence of Lewis acidic metal salts. The mechanism of this reaction is discussed and elucidated with DFT calculations. The results underline the fascinating similarity between phosphorus‐rich and isolobal carbon compounds. The new bicyclic octaphosphane 2 shows a dynamic behavior in solution and reacts with [AuCl(tht)] (tht=tetrahydrothiophene) to give a mono‐ ([AuCl(2‐κP (3))], 3) and a dinuclear complex ([(AuCl)(2)(2‐κP (3),κP (3′))], 4). With cis‐[PdCl(2)(cod)] (cod=1,5‐cyclooctadiene), the chelate complex ([PdCl(2)(2‐κ(2) P (2),P (2′))], 5) with a different coordination mode of the ligand was obtained.