Thermal [2 + 2] Cycloadditions between the Metallodiphosphene (η⁵-C₅Me₅)(CO)₂Fe−PP−Mes* and a Phosphaalkyne

Abstract

The synthesis of trans-1,2-dihydro-1-(2,4,6-tri-tert-butylphenyl)-2-(dicarbonyl-η5-pentamethylcyclopentadienylferrio)-4-diisopropylamino-1,2,3-triphosphete (9) was conducted by treating 1-(dicarbonyl-η5-pentamethylcyclopentadienylferrio)-2-(2,4,6-tri-tert-butylphenyl)diphosphene (7) with an equimolar amount of 2-diisopropylamino-1-phosphaethyne (2b). Monitoring the reaction by 31P{1H} NMR evidenced the formation of trans-1,2-dihydro-1-(dicarbonyl-η5-pentamethylcyclopentadienylferrio)-2-(2,4,6-tri-tert-butylphenyl)-4-diisopropylamino-1,2,3-triphosphete (8) as an intermediate, which in solution slowly isomerized to the final product 9.

Reaction of a Diphosphene Complex with Dimethylcyanamide

“…The most likely mechanism for the formation of 2 implies the initial formation of a zwitterionic adduct ( 4 ) by nucleophilic attack of the C⋮N nitrogen onto the PP double bond. It is interesting to note that a similar adduct has been postulated in the reaction of i Pr 2 N−C⋮P with a metalladiphosphene …”

“…Only a few [2+2] cycloaddition reactions have been described with diphosphenes or their complexes . These include the reaction of a metalladiphosphene with electron-poor alkenes, the condensation of a diphosphene complex with alkynes, and the reaction of a metalladiphosphene with an aminophosphaalkyne . In the context of the phosphorus−nitrogen vs phosphorus−carbon analogies, it was interesting to transpose the last reaction with the nitrogen analogues of aminophosphaalkynes.…”

Phosphaorganische Chemie: Panorama und Perspektiven

“…Grobe und Weber et al gelang des Weiteren die [2+2]‐Cycloaddition eines Diphosphens und eines Phosphaalkins [Gl. (38) ] 104. Das im ersten Schritt gebildete Addukt isomerisiert langsam bei Raumtemperatur.…”

Diverse Reactions of o-Carborane-Fused Silylenes with C≡E (E = C, P) Triple Bonds

“…Compound 5 crystallizes in the monoclinic space group P 2 1 / c and can be deemed as a 1,2,3-triphosphetene derivative of silylene formed via a formal condensation of two 1b and three AdCP molecules (Figure ). The core structure of 5 comprises a slightly distorted CP 3 four-membered ring in the middle, whose structure parameters are comparable to those of the triphosphetenes derived from N-heterocyclic carbenes. , The Si1–C14 (1.754(4) Å) and Si2–C66 (1.773(4) Å) bonds are significantly shorter in length than Si1–C2 (1.943(5) Å) and Si2–C29 (1.952(5) Å) bonds, which display a SiC double bond character.…”