- Rhodium-catalyzed, efficient deutero- and tritiosilylation of carbonyl compounds from hydrosilanes and deuterium or tritium
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A cationic rhodium compound which is an active catalyst for both the hydrogen isotope exchange in hydrosilanes and the hydrosilylation of carbonyl compounds permits, in a one-flask, two-step procedure, efficient deutero- and tritiosilylations using SiEt3H under D2 (0.5 bar) or T2, at low catalyst loadings (0.1-0.5 mol %).
- Rubio, Miguel,Campos, Jesuus,Carmona, Ernesto
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supporting information; experimental part
p. 5236 - 5239
(2011/12/15)
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- Cationic ethylzinc compound: A benzene complex with catalytic activity in hydroamination and hydrosilylation reactions
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The tight ion pair [EtZn(η3-C6H 6)][CHB11Cl11]?C6H6 (1?C6H6) was obtained through β-hydrogen abstraction and concomitant ethene elimination from Et2Zn with the trityl salt [Ph3C][CHB11Cl11]. This ionlike species shows catalytic activity in hydrosilylation and intramolecular hydroamination reactions. The amine adduct {CH2CHCH 2C(Ph2)CH2NH2}3ZnCB 11Cl11 (3), which features a rare transition metal-carborane σ bond, was isolated from a hydroamination experiment.
- Wehmschulte, Rudolf J.,Wojtas, Lukasz
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scheme or table
p. 11300 - 11302
(2012/01/04)
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- Iodine- or Iodine Monobromide-Catalyzed Alkoxy-Alkoxy Exchange Reactions of Alkylalkoxysilanes: Formation of the Catalyst-Alkoxysilane Complexes and the Reaction Mechanism
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The formation of charge-transfer complexes of iodine and of iodine monobromide with alcohols and alkoxysilanes has been established spectroscopically, and the formation constants of iodine-ethoxytriethylsilane and iodine-diethoxydimethylsilane complexes has been determined as 0.55+/-0.01 and 0.61+/-0.02, respectively.On the basis of these observations and the kinetic information recently reported, the previously proposed mechanism for the iodine or iodine monobromide catalyzed alkoxy-alkoxy exchange reactions of alkoxysilanes is dicussed afresh.It has been confirmed that a mechanism involving a four-centered transition state containing a CT-complex is most favorable.
- Ito, Katsuko,Ibaraki, Takeshi
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p. 2853 - 2858
(2007/10/02)
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- Alcoholysis Equilibria of Triethylalkoxysilanes Catalyzed by Iodine or Iodine Monobromide
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The equilibrium constants K of alcoholysis of triethylalkoxysilanes were determined at 20 degC and 40 degC.Iodine monobromide was used to promote the reactions associated with the tertiary alkoxyl groups, while the other reactions proceeded in the presence of iodine.The K values of the reaction systems with ethoxyl or propoxyl-primary, secondary, and tertiary alkoxyl pairs were 1 or above, about 0.5, and about 0.05, respectively.These values reflect the extent of the binding abilities of the alkoxyl groups to silicon, which is in the expected order of primary>secondary>tertiary alkoxyl groups.A mechanism is postulated for the reaction which involves participation by the iodine or iodine monobromide.
- Ito, Katsuko,Ibaraki, Takeshi
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p. 2973 - 2975
(2007/10/02)
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