85316-45-6Relevant academic research and scientific papers
Polysilane-supported transition metal catalyst for liquid phase reaction
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Page/Page column 21-22, (2012/12/13)
The present invention provides a polysilane-supported transition metal catalysts or a polysilane/inorganic compound-supported transition metal catalysts, wherein various types of transition metals are supported by polysilane compounds, or combination of polysilanes and inorganic compounds. The catalysts of the present invention are hardly soluble in hydrocarbons and alcohols and are useful as catalysts in heterogeneous system for various organic synthetic reactions using the above solvents. Polysilanes supporting transition metals are easily crosslinkable by thermal treatment, microwave irradiation, UV irradiation or chemical methods such as hydrosilylation reaction and are changed to be insoluble in various solvents keeping high catalytic activity. Moreover, the stability and operability of polysilane-supported transition metal catalysts will be improved by the support thereof on inorganic compounds. These polysilane-supported transition metal catalysts show a high catalytic activity in hydrogenation reaction, hydrosilylation reaction, Heck reaction, Suzuki-Miyaura coupling reactions and the like. The catalyst is easily recoverable and reusable and the leakage of metals is extremely few.
Carbanion Rearrangements by Intramolecular 1,ω Proton Shifts, IV. The Reaction of ω,ω-Diphenylalkyllithium Compounds: Proof for an Intramolecular Transmetallation Reaction by Crossover Experiments Using Isotopic Labelled Starting Material
Maercker, Adalbert,Passlack, Michael
, p. 710 - 723 (2007/10/02)
3,3-Diphenylpropyllithium (2) and 2-(9-fluorenyl)ethyllithium (43) do not show a 1,3 proton shift but splitt off ethylene.On the other hand 4,4-diphenylbutyllithium (19) in diethyl ether can be forced to rearrange to 1,1-diphenylbutyllithium (18) by the addition of THF.The half reaction time for this 1,4 proton shift was found to be about 4 minutes.Proof for the intramolecular character of this transmetallation reaction was obtained by crossover experiments with specifically deuterated starting material.The 1,5 proton shift with 5,5-diphenylpentyllithium (12) occurs considerably slower than the 1,4 shift with 4,4-diphenylbutyllithium (19).The rearrangement also takes place in pure diethyl ether although with a half reaction time of about 2 days.Only 3-(9-fluorenyl)propyllithium (41) in diethyl ether spontaneously shows rearrangement already at -30 deg C, whereby 9-propyl-9-fluorenyllithium (42) is formed by a 1,4 proton shift.A 1,ω phenyl migration according to Grovenstein-Zimmerman in no case could be observed.
