76347-13-2Relevant articles and documents
Preparation of tungsten-based olefin metathesis catalysts supported on alumina
Yuan, Jian,Townsend, Erik M.,Schrock, Richard R.,Goldman, Alan S.,Mueller, Peter,Takase, Michael K.
, p. 1985 - 1992 (2011)
A new tungsten alkylidene complex, W(NAr)(CHCMe2Ph)(OHIPT- NMe2)(pyrrolide) {Ar=2,6-(i-Pr)2C6H 3; HIPT-NMe2=2,6-[2,4,6-(i-Pr)3C 6H2]2-4-NMe2-C6H 2}, has been synthesized and shown to be highly selective for Z homocoupling metathesis of selected terminal olefins in pentane, as is W(NAr)(CH2CH2CH2)(OHIPT)(pyrrolide) (5). Both 5 and W(NAr)(CHCMe2Ph)(OHIPT-NMe2)(pyrrolide) (6) are adsorbed onto calcined alumina. Control experiments and metathesis homocoupling of four substrates lead to the conclusions that 5 is largely adsorbed in a reaction that liberates HIPTOH, while 6 is adsorbed largely through an interaction between the dimethylamino group and an acidic site on the surface. There is no evidence that any adsorbed catalyst can give rise to Z selectivity of a magnitude equal to that found in a homogeneous reaction involving 5 or 6. Copyright
SYNTHESIS OF BORONIC ESTERS AND BORONIC ACIDS USING GRIGNARD REAGENTS
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Paragraph 0123, (2013/03/26)
Boronic esters and boronic acids are synthesized at ambient temperature in an ethereal solvent by the reaction of Grignard reagents with a boron-containing substrate. The boron-containing substrate may be a boronic ester such as pinacolborane, neopentylglycolborane, or a dialkylaminoborane compound such as diisopropylaminoborane. The Grignard reagents may be preformed or generated from an alkyl, alkenyl, aryl, arylalkyl, heteroaryl, vinyl, or allyl halide compound and Mg°. When the boron-containing substrate is a boronic ester, the reactions generally proceed at room temperature without added base in about 1 to 3 hours to form a boronic ester compound. When the boron-containing substrate is a dialkylaminoborane compound, the reactions generally proceed to completion at 0°C in about 1 hour to form a boronic acid compound.
Practical and efficient applications of novel dioxaborolanes and dioxaborinanes in the synthesis of corresponding boronates and their use in the palladium-catalyzed cross coupling reactions
Myslinska, Malgorzata,Heise, Glenn L.,Walsh, Dana J.
experimental part, p. 2937 - 2941 (2012/07/31)
The syntheses of boronates derived from the reaction of dioxaborolanes and dioxaborinanes with either organolithium or organomagnesium reagents are investigated along with their subsequent use in the palladium cross coupling reaction. The intrinsic stability of these cyclic esters contributes to their facile reaction with both lithium and magnesium nucleophiles at mild and safe conditions. We have found that many of the reactions proceed at room temperature which is a significant improvement over the traditional routes which require cryogenic temperatures. The scope of these reactions and their practical application to large scale process synthesis is described.
