Beiträge zur Chemie des Phosphors. 94. Tetraphenyl‐cyclotetraphosphan, (PPh)₄, und 1,2,3‐Triphenyl‐4‐tert‐butyl‐cyclotetraphosphan, (PPh)₃(PBu^t)

Abstract

Die homocyclischen Phosphor‐Vierringverbindungen Tetraphenyl‐cyclo‐tetraphosphan, (PPh)4 (1), und l,2,3‐Triphenyl‐4‐tert‐butyl‐cyclotetraphosphan, (PPh)3(PBut) (2), werden bei der [3+l]‐Cyclokondensation von K(Ph)PP(Ph)P(Ph)K oder Me3Si(Ph)PP(Ph)P(Ph)SiMe3 mit PhPCl2 bzw. ButPCl2 unter geeigneten Reaktionsbedingungen als Hauptprodukte erhalten. Während sich 1 bei Raumtemperatur in Lösung weitgehend in das oligomere (PPh)5 um‐lagert, ist 2 unter diesen Bedingungen kinetisch bemerkenswert beständig. Die 31P‐NMR‐Parameter der gemischt‐substituierten Vierring‐Verbindung 2 werden mitgeteilt und diskutiert.

Metallacycle Transfer Routes to Main-Group Phosphacycles

“…31 P NMR (25 °C, C 6 D 6 ): δ −48.0 (s). 1 H NMR and 13 C{ 1 H} NMR data were consistent with those reported in the literature …”

“…Much of our recent published work illustrates the reactive nature of Zr−P bonds; thus, we inferred that the four-membered metallacycle 1 would be susceptible to metallacycle transfer reactions. As surmised, compound 1 reacted cleanly with phenyldichlorophosphine in solution at 25 °C to yield Cp 2 ZrCl 2 and the known phosphacycle (PPh) 4 ( 4 ), the latter in 82% isolated yield. The identity of 4 was established by comparison of the spectral data to the literature data as well as a crystallographic structural study (Figure ), which confirmed the previously predicted “all- trans ” conformation.…”

Contributions to the chemistry of phosphorus. 218. Monocyclic and polycyclic phosphines

“…On the other hand, in 49 there is no evidence for an intraor intermolecular metal/ hydrogen exchange. Compounds in which the hydrogen atoms of 49 and 51 are substituted by trimethylsilyl or organic groups have been obtained by reaction of (Me3Si)3P7 (53) with 41 or by reaction of white phosphorus with organolithium derivatives, respectively.234 These derivatives of 49 also exhibit the fluctuating bond phenomenon.…”

“…Compound 41 is stabilized by the addition of three solvent molecules (THF, DME) and decomposition occurs upon their removal. Reaction with chloro(trimethyl)silane furnishes the silyl derivative 53,225 which is also accessible from P4, Na/K alloy, and MesSiCl.236 Protolysis of 53 under mild conditions yields the phosphorus hydride 52 which can be converted back to 41 by metalation. 225 The reactions of 41 with alkyl halides furnish the corresponding trialkylheptaphosphanes P7R3 (see section V).…”

“…Up to the present, the only such compound to be isolated in the pure state is heptaphosphane(3) (52), which is obtainable by the mild methanolysis of the silyl derivative 53.225 Compound 52 is amorphous to -40 °C (Me3Si)3P7 + 3MeOH -* P7H3 + 3Me3SiOMe (53) 53 52…”