1833-32-5Relevant articles and documents
Hydrogen/Halogen Exchange of Phosphines for the Rapid Formation of Cyclopolyphosphines
Barrett, Adam N.,Woof, Callum R.,Goult, Christopher A.,Gasperini, Danila,Mahon, Mary F.,Webster, Ruth L.
supporting information, p. 16826 - 16833 (2021/11/04)
The hydrogen/halogen exchange of phosphines has been exploited to establish a truly useable substrate scope and straightforward methodology for the formation of cyclopolyphosphines. Starting from a single dichlorophosphine, a sacrificial proton "donor phosphine"makes the rapid, mild synthesis of cyclopolyphosphines possible: reactions are complete within 10 min at room temperature. Novel (aryl)cyclopentaphosphines (ArP)5 have been formed in good conversion, with the crystal structures presented. The use of catalytic quantities of iron(III) acetylacetonate provides significant improvements in conversion in the context of diphosphine (Ar2P)2 and alkyl-substituted cyclotetra- or cyclopentaphosphine ((AlkylP)n, where n = 4 or 5) formation. Both iron-free and iron-mediated reactions show high levels of selectivity for one specific ring size. Finally, investigations into the reactivity of Fe(acac)3 suggest that the iron species is acting as a sink for the hydrochloric acid byproduct of the reaction.
The β-silicon effect. 4: Substituent effects on the solvolysis of 1-alkyl-2-(aryldimethylsilyl)ethyl trifluoroacetates
Fujiyama, Ryoji,Alam, Md. Ashadul,Shiiyama, Aiko,Munechika, Toshihiro,Fujio, Mizue,Tsuno, Yuho
experimental part, p. 819 - 827 (2011/04/24)
Solvolysis rates of 2-(aryldimethylsilyl)-1-methylethyl and 2-(aryldimethylsilyl)-1-tert-butylethyl trifluoroacetates were determined conductimetrically in 60% (v/v) aqueous ethanol. The effects of aryl substituents at the silicon atom on the solvolysis rates at 50 °C were correlated with σmacr; parameters of r+ = 0.15 with the Yukawa-Tsuno equation, giving ρ values of-1.5 for both secondary α-Me and α-tert-Bu systems. The ρ values for those secondary systems are less negative than-1.75 for the 2-(aryldimethylsilyl)ethyl system that proceeds by the Eaborn (non-vertical) mechanism, while they are distinctly more negative than-0.99 for 2-(aryldimethylsilyl)-1-phenylethyl system that should proceed by the Lambert (vertical) mechanism. There was a fairly linear relationship between the reaction constants (ρ) for the β-silyl substituent effects and the solvolysis reactivities for a series of β-silyl substrates. The solvolyses of the α-Me and tert-Bu substrates proceed through the transition state (TS) with an appreciable degree of the β-silyl participation, close to the Eaborn (non-vertical) TS rather than to the Lambert (vertical) TS. Copyright
N-ETHYLENEDIAMINES
Hu, Chunye,He, Ji-Gang,O'Brien, D. H.,Irgolic, K. J.
, p. 31 - 38 (2007/10/02)
A series of N-organosilylalkyl-substituted ethylenediamines, R3Si(CH2)nNHCH2CH2NH2 (R = CH3, C6H5 or 4-CH3C6H4; n = 1 or 3), were prepared by the reaction of haloalkylsilanes with ethylenediamine.The cleavage of a methyl group from silicon by concentrated sulfuric acid was used for the preparation of 1,3-bis-1,1,3,3-tetramethyldisiloxane.The proton and carbon-13 NMR spectra of these compounds are reported.
