88081-26-9Relevant academic research and scientific papers
A kinetic study of the generation of terminal phosphinidene complexes from 7-phosphanorbornadiene complexes. X-ray crystal structure analysis of the dimers of terminal phosphinidene complexes
Marinetti, Angela,Charrier, Claude,Mathey, Fran?ois,Fischer, Jean
, p. 2134 - 2138 (2008/10/08)
A kinetic study of the thermal decomposition of a 7-phenyl-7-phosphanorbornadiene P-W(CO)5 complex in the presence of aniline, tolan, and cyclooctene has been performed at 105, 115, 117, and 125°C. The kinetics of this decomposition are first order in the concentration of the phosphanorbornadiene complex and do not depend on the concentration and nature of the trapping reagent. These results give additional support to the intermediacy of a terminal phosphinidene complex, [PhP=W(CO)5], in such a decomposition. The activation energy of the process is calculated to be 33 ± 1 kcal mol-1. The thermolysis of the same 7-phosphanorbornadiene at 55°C in the presence of CuCl as a catalyst gives a dimeric complex, [PhP= PPh][W(CO)5]3, in which both the phosphorus atoms and the P=P double bond are complexed by the three W(CO)5 units as shown by X-ray crystal structure analysis.
The carbene-like behavior of terminal phosphinidene complexes toward olefins. A new access to the phosphirane ring
Marinetti, Angela,Mathey, Fran?ois
, p. 456 - 461 (2008/10/08)
In the presence of copper(I) chloride, (7-R-7-phosphanorbornadiene)P-M(CO)5 complexes (M = Cr, W) decompose around 55°C to give the corresponding terminal phosphinidene complexes RP=M(CO)5. These transient phosphinidene complexes react in situ with olefins to give phosphirane complexes. The stereochemistry of the starting olefin is retained in the phosphirane ring, thus suggesting a concerted process. The reaction with 1,3-dienes yields 2-vinylphosphirane complexes that rearrange around 100°C to the corresponding phospholenes. On the contrary, the reaction with α,β-unsaturated ketones gives directly the 1,2-oxaphospholene complexes, but the formation of an intermediate 2-acylphosphirane cannot be excluded. With methyl methacrylate, the 2-(methoxycarbonyl)phosphirane is formed and is apparently stable. With ethyl vinyl ether, the 2-ethoxyphosphirane transiently obtained is so reactive that neutral water cleaves the P-C(OEt) bond of the ring to give a secondary α-phosphinoacetaldehyde that is stabilized as its P-W(CO)5 complex. An excess of vinyl ether also reacts with the 2-ethoxyphosphirane to give a 2,4-diethoxyphospholane. In all its reactions, PhP=W(CO)5 apparently behaves as a singlet electrophilic carbene.
