29163-98-2Relevant academic research and scientific papers
Electrocyclic reactions of siloles: A combined experimental and theoretical study
Meyer-Wegner, Frank,Wender, Josef H.,Falahati, Konstantin,Porsch, Timo,Sinke, Tanja,Bolte, Michael,Wagner, Matthias,Holthausen, Max C.,Lerner, Hans-Wolfram
, p. 4681 - 4690 (2014/05/06)
The reaction of 4-chloro-1,2-dimethyl-4-supersilylsila-1-cyclopentene (2 a) with Li[NiPr2] at -78 °C results in the formation of the formal 1,4-addition product of the silacyclopentadiene derivative 3,4-dimethyl-1- supersilylsila-1,3-cyclopentadiene (4 a) with 2,3-dimethyl-4-supersilylsila-1,3- cyclopentadiene (5 a). In addition the respective adducts of the Diels-Alder reactions of 4 a+4 a and 4 a+5 a were obtained. Compound 4 a, which displays an s-cis-silacyclopentadiene configuration, reacts with cyclohexene to form the racemate of the [4+2] cycloadduct of 4 a and cyclohexene (9). In the reaction between 4 a and 2,3-dimethylbutadiene, however, 4 a acted as silene as well as silacyclopentadiene to yield the [2+4] and [4+2] cycloadducts 10 and 11, respectively. The constitutions of 9, 10, and 11 were confirmed by NMR spectroscopy and their crystal structures were determined. Reaction of 4-chloro-1,2-dimethyl-4-tert-butyl-4-silacyclopent-1-ene (2 c) with KC 8 yielded the corresponding disilane (12), which was characterized by X-ray crystal structure analysis (triclinic, Pβar 1$). DFT calculations are used to unveil the mechanistic scenario underlying the observed reactivity. Added value: The intermediately formed 2 H-silole 4 a dimerizes to three different products in a 1:1:1 ratio (see scheme): the formal 1,4-addition product of 4 a and 5 a and the Diels-Alder products of 4 a with 4 a and 4 a with 5 a. Compound 4 a undergoes Diels-Alder reactions with cyclohexene and dimethylbutadiene. DFT calculations elucidate the underlying reaction mechanisms.
Diels-Alder chemistry of siloles and their transformation into cyclohex-2-ene-1,4-cis-diols
Stevens, Andrew C.,Pagenkopf, Brian L.
supporting information; experimental part, p. 3658 - 3661 (2010/10/20)
The synthesis of siloles with substitution patterns that are continuative toward natural product synthesis are described. Their reactivity in Diels-Alder chemistry was explored through thermal, Lewis acid, and high-pressure reactions. Furthermore, bicycli
Palladium-catalyzed silylene-1,3-diene [4 + 1] cycloaddition with use of (aminosilyl)boronic esters as synthetic equivalents of silylene
Ohmura, Toshimichi,Masuda, Kohei,Takase, Ichiro,Suginome, Michinori
supporting information; experimental part, p. 16624 - 16625 (2010/02/16)
(Chemical Equation Presented) Silylboronic esters bearing a dialkylamino group on the silicon atoms reacted with 1,3-dienes in the presence of a palladium catalyst to give silacyclopent-3-enes (i.e., 2,5-dihydrosiloles) in high yields via efficient silyle
Chemistry of Substituted (2-Butene-1,4-diyl)magnesium: A Facile Approach to Complex Carbocycles, Functionalized Ketones and Alcohols, and Silicon-Containing Heterocycles
Rieke, Reuben D.,Xiong, Heping
, p. 3109 - 3118 (2007/10/02)
Highly reactive magnesium reacts with a wide variety of substituted 1,3-dienes to give the corresponding substituted (2-butene-1,4-diyl)magnesium complexes.Reactions of symmetrical (2-butene-1,4-diyl)magnesium with α,ω-alkylene dihalides form three-, four-, five-, and six-membered carbocycles.Significantly, the cyclizations are always stereospecific and completely regioselective.Depending on the initial 1,3-diene and specific electrophiles, uncyclized products can be obtained.Stepwise reactions of (2,3-dimethyl-2-butene-1,4-diyl)magnesium with two different electrophiles afford polyfunctionalized ketones with the generation of a quaternary center.Formal 1,2-additions can be effected in this manner.Substituted five- and six-membered cyclic ketones can also be synthesized in one step by this approach.Treatment of unsymmetrical (2-butene-1,4-diyl)magnesium complexes with triorganosilyl chlorides followed by cyclohexanone results in additions across a terminal double bond with high regioselectivity.Silicon-containing heterocycles or spiro compounds can be readily synthesized by using the bis-Grignard reagents.
Organocalcium Chemistry: Preparation and Reactions of Highly Reactive Calcium
Wu, Tse-Chong,Xiong, Heping,Rieke, R. D.
, p. 5045 - 5051 (2007/10/02)
A highly reactive form of calcium was prepared by the reduction of Ca(II) salts with preformed lithium biphenylide.Remarkably, this activated calcium undergoes oxidative addition to organic bromides, chlorides, or even fluorides to form the organocalcium reagents under very mild conditions in high yields.The resulting organocalcium compounds undergo Grignard-type reactions.Transmetalation with Cu(I) salts forms calcium cuprate reagents which undergo a variety of cross-coupling reactions.The activated calcium reacts with 1,3-dienes to yield the corresponding 2-butene-1,4-diylcalcium complexes.These bis-organocalcium reagents can undergo dialkylation reactions with α,ω-alkylene dihalides and dichlorosilanes to form the corresponding 3-, 5-, and 6-membered ring derivatives.Significantly, these reactions are highly stereospecific and regioselective.
Facile Formation of Substituted 2-Butene-1,4-diylmagnesium Using Highly Reactive Magnesium: A Simple Approach to Complex Carbocycles and Functionalized Ketones
Xiong, Heping,Rieke, Reuben D.
, p. 3247 - 3249 (2007/10/02)
Substituted 2-butene-1,4-diylmagnesium compounds are readily prepared using highly reactive magnesium.Reactions with organodihalides yield 4-, 5-, and 6-membered carbocycles.In some cases, the initial monoalkylated intermediates can be reacted with other electrophiles.Polyfunctionalized ketones can be prepared in this manner.Depending on the initial 1,3-diene and by the proper choice of electrophiles, either 1,2-, 1,4-, or 2,1-additions may be observed.
Preliminary communication. Kinetic spectroscopy of diphenylgermylene Ph2Ge following laser flash photolysis of bis(trimethylsilyl)diphenylgermane (Me3Si)2GePh2
Konieczny, Stanislaw,Jacobs, S. Joshua,Wilking, Janet K. Braddock,Gaspar, Peter Paul
, p. C17 - C22 (2007/10/02)
A transient, λmax 445 nm, was observed in the 266 nm laser flash photolysis of cyclohexane solutions of (Me3Si)2GePh2, and rate constants were recorded for its disappearance in the presence of various trapping agents.The reactivity profile is in accord with the identification of the carrier as diphenylgermylene Ph2Ge, that dimerizes to tetraphenyldigermene Ph2Ge=GePh2, λ7max3 320 nm.
