15181-08-5Relevant academic research and scientific papers
Rethinking Basic Concepts-Hydrogenation of Alkenes Catalyzed by Bench-Stable Alkyl Mn(I) Complexes
Weber, Stefan,St?ger, Berthold,Veiros, Luis F.,Kirchner, Karl
, p. 9715 - 9720 (2019/10/14)
An efficient additive-free manganese-catalyzed hydrogenation of alkenes to alkanes with molecular hydrogen is described. This reaction is atom economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. The most efficient precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid hydrogenolysis to form the active 16e Mn(I) hydride catalyst [Mn(dippe)(CO)2(H)]. A range of mono- A nd disubstituted alkenes were efficiently converted into alkanes in good to excellent yields. The hydrogenation of 1-alkenes and 1,1-disubstituted alkenes proceeds at 25 °C, while 1,2-disubstituted alkenes require a reaction temperature of 60 °C. In all cases, a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar were applied. A mechanism based on DFT calculations is presented, which is supported by preliminary experimental studies.
Continuous synthesis of organozinc halides coupled to Negishi reactions
Alonso, Nerea,Miller, L. Zane,De M. Muoz, Juan,Alczar, Jesus,McQuade, D. Tyler
supporting information, p. 3737 - 3741 (2015/01/16)
The Negishi cross-coupling is a powerful C-C bond forming reaction. The method is less commonly used relative to other cross-coupling methods in part due to lack of availability of organozinc species. While organozinc species can be prepared, problems wit
Process for the carboxylation of aryl halides with palladium catalysts
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Page/Page column 5-6, (2011/05/04)
A process for the carboxylation of an aryl halide to yield an aryl carboxylic acid, in which the aryl halide and CO2 are contacted in an organic solvent under inert atmosphere and in the presence of a reducing agent and an adequate catalyst system.
Palladium-catalyzed direct carboxylation of aryl bromides with carbon dioxide
Correa, Arkaitz,Martin, Ruben
supporting information; scheme or table, p. 15974 - 15975 (2010/02/15)
(Chemical Equation Presented) A novel protocol for the direct carbon dioxide insertion (CO2) into aryl halides in a catalytic manner is presented herein. Unlike other carboxylation methods using CO2, there is no need for the synthesis of the corresponding organometallic intermediates. Additionally, and in contrast to the well-established carbonylation processes, our protocol does not use highly toxic CO for the preparation of benzoic acids. Furthermore, this method is distinguished by its mild conditions, allowing the tolerance of a wide range of functional groups and substitution patterns. The crucial step of the process involves a challenging catalytic CO2 insertion into Pd-C bonds. Copyright
Palladium-catalyzed cross-coupling alkylation of arenediazonium o-benzenedisulfonimides
Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
, p. 474 - 478 (2008/09/21)
Arenediazonium o-benzenedisulfonimides were reacted with tetramethyltin, tetrabutyltin or trialkylboranes. The reactions, carried out in the presence of palladium(II) derivatives as precatalysts, gave the methylation and alkylation products with good over
A novel 1,2-migration of arylzincates bearing a leaving group at benzylic position: Application to a three-component coupling of p-iodobenzyl derivatives, trialkylzincates, and electrophiles leading to functionalized p- substituted benzenes
Harada, Toshiro,Kaneko, Takayuki,Fujiwara, Takayuki,Oku, Akira
, p. 9317 - 9332 (2007/10/03)
A three-component coupling of p-iodobenzyl derivatives, trialkylzincates, and electrophiles is described. Lithium trialkylzincates (R3ZnLi) react with p-iodobenzyl methanesulfonate to give benzylzinc reagents p-RC6H4CH2Zn(L). The reaction proceeds through a mechanism involving initial iodine/zinc exchange and the 1,2-migration of the resulting arylzincates. The benzylzinc reagents, thus prepared, are subsequently used in coupling reaction with electrophiles such as aldehydes, ketones, acyl chlorides, tosyl cyanide, and chlorosilanes to give a variety of functionalized p-substituted benzenes. Reactions under Barbier conditions in which the corresponding benzylzinc reagents are generated in the presence of electrophiles work well for Me3ZnLi and for magnesium zincates R3ZnMgBr derived from Grignard reagents. Generation of secondary benzylzinc reagents starting from diethyl 1-(p-iodophenyl)ethyl phosphate and their reaction with electrophiles are also achieved under Barbier conditions. Ketones, allyl bromides, and chlorosilanes are successfully used as electrophiles under these conditions.
Arene-Metal Complexes. 12. Reaction of Substituted (Benzene)tricarbonylchromium Complexes with n-Butyllithium
Card, Roger J.,Trahanovsky, Walter S.
, p. 2560 - 2566 (2007/10/02)
Reaction of a series of substituted (benzene)tricarbonylchromium complexes with n-butyllithium has been examined.The reaction appears to proceed via proton abstraction to yield an (aryllithium)tricarbonylchromium intermediate which may then be quenched by the addition of primary alkyl halides,usually methyl iodide.New alkylated complexes may be obtained,or the material may be decomplexed to yield alkylated benzene derivatives.In this manner,(monoalkylbenzene)tricarbonylchromium complexes yield mainly m-dialkylbenzenes;(fluorobenzene)tricarbonylchromium yields o-fluorotoluene;(anisole)tricarbonylchromium yields mainly 2,6-dimethylanisole;and (N,N-dimethylaniline)tricarbonylchromium yields several isomeric N,N-dimethyltoluidines.(Iodobenzene)tricarbonylchromium undergoes metal-halogen exchange with n-butyllithium and may be converted to either toluene or n-butylbenzene depending on the reaction conditions.Comparison with known chemistry of the uncomplexed analogues demonstrates the strongly activating effect of the tricarbonylchromium moiety on these reactions.It is especially interesting that under these conditions reaction of (fluorobenzene)tricarbonylchromium with n-butyllithium results in proton abstraction rather than net nucleophilic displacement,as observed when less basic nucleophiles are used.
