1,3,5,7‐Tetraphosphabarrelen, ein neues cyclisches Tetramer der Phosphaalkine

Abstract

Die Chemie der Phosphaalkine (RC-P) hat wesentliche Impulse durch die Verwendung von Ubergangsmetalltemplaten in Cyclooligomerisierungen erhalten [']. Wichtige Stationen auf diesem sich noch immer sturmisch entwickelnden Gebiet ist die Cyclodimerisierung von tert-Butylphosphaacetylen 5 zu den y4-1,3-Diphosphacyclobutadienkomplexen von Cobalt['] und Rhodium, 1 [jl, die unerwartete Bildung der tricyclischen Zirconium-und Hafniumkomplexe 2 aus 5[41 sowie die Cyclotrimerisierung von 5 zum 1,3,5-Triphospha-Dewar-Benzolkomplex 3 niit Vanadium als Zentralatom[s]. 1 2 M = Co, Rh M=Zr,Hf 3 Von diesen Metallkomplexen mit heterocyclischen Liganden haben sich bisher nur die Zirconium-und Hafniumverbindungen 2 als ergiebige Quellen zur Synthese neuartiger Phosphaheterocyclen e r~i e s e n [~~. 'I, wobei besonders die Synthese des symmetrischen Tetraphosphacubans aus 2 bemerkenswert ist[']. Wir berichten hier erstmals uber die erfolgreiche Cyclotetramerisierung des Phosphaalkins 5 am Bis(cyc1ooctatetraen)-Zirconiumkomplex 4 zum y4-1 ,3,5,7-Tetraphosphabarrelen-Zirco-niumkomplex6, aus dem mit Hilfe von Hexachlorethan das 1,3,5,7-Tetraphosphabarrelenderivat 7 als neues, cyclisches Tetramer des Phosphaalkins 5 freigesetzt werden kann (Schema 1). 4 6 Schema 1. a: Toluol. 2 d. 70 C. -cot; b: Pentan. 12 h. -78 -20"C, -C,CI,, -[(cotJZrCI,]. TS 2 116 c) VCH Verlugsgrsellsrhafl mbH. 0-69451 Weinhetin, 1995

Novel Tetraphosphabarrelene and -semibullvalene Derivatives by Reactions of 2,4,6-Tri-tert-butyl-1,3,5-triphosphabenzene with Phosphaalkynes⋆

“…(i) Aminophosphaalkenes are not suited for cycloadas observed for the corresponding hydrocarbon derivatives (Cope rearrangement) was not detected for 10 at room tem-dition reactions due to the loss of olefinic character, Novel Tetraphosphabarrelene and -semibullvalene Derivatives FULL PAPER 2,4,6,3,5, 4 isomers favour the semibullvalene system over the with those of an authentic sample. [6] cuneane structure.…”

“…Cleavage of 7 with C 2 Cl 6 yields the 1,3,5,7-tetraphosphabarrelene derivative 8a, which had been isolated before from the reaction of bis(cyclooctatetraene)zirconium with 5a. [6] It is of particular interest that the valence In 1998 Regitz et al based on the use of the strong Lewis acid tBuNϭVCl 3 asEur. …”

“…[6] cuneane structure. [4,6, 2, 6,3,4,8 ]octa-2,5-diene (10): 80 mg (0.27 mmol) of the triphosphabenzene derivative 4 were placed in an ampoule with break seals and an NMR tube together with 0.5 ml [D 8 ]toluene. 45 mg (0.31 mmol) of di(isopropyl)aminophosphaethyne 9 were then introduced by vacuum condensation at Ϫ196°C.…”

Imidovanadium(V) Complexes as Reaction Partners for Kinetically Stabilized Phosphaalkynes: Synthesis of 1,2,4-Azaphosphavanada(V)-cyclobutenes, 1,3,5-Triphosphabenzenes, and 1H-1,2,4-Azadiphospholes

“…[5,6,7] In general, phosphaalkynes preferentially undergo cyclization to afford 1,3-diphosphacyclobutadienes in the presence of electron-rich transition metal fragments, while in the presence of the in situ generated 14 valence electron species Cp 2 Zr they react to furnish the tricyclic complexes 3. [5,6,7] In general, phosphaalkynes preferentially undergo cyclization to afford 1,3-diphosphacyclobutadienes in the presence of electron-rich transition metal fragments, while in the presence of the in situ generated 14 valence electron species Cp 2 Zr they react to furnish the tricyclic complexes 3.…”

Organophosphorus Compounds, 103. Thermal Transformation of Kinetically Stabilized Phosphaalkynes with Phosphinidene Precursors. Synthesis of Phosphorus‐Carbon Cage Compounds by Cocyclooligomerization Processes

“…Cyclooligomerization reactions of the kinetically stabilized phosphaalkynes P d -R constitute a current research topic of particular interest because of its dynamic development [2][3][4][5][6][7]. In contrast to the homologous nitriles, phosphaalkynes show pronounced tendencies for the formation of oligomeric polycyclic systems and, above all, fascinating cage compounds both under thermal and under transition metal-catalyzed reaction conditions.…”