Eine katalytisch verlaufende asymmetrische Synthese

Bogdanović, Borislav; Henc, Biserka; Meister, Burkhard; Pauling, Horst; Wilke, Günther

doi:10.1002/ange.19720842118

Cited by 46 publications

(8 citation statements)

References 11 publications

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“…Since the first report by Alderson in 1965, several groups have demonstrated that hydrovinylation reactions can, in principle, be catalyzed by suitable transition‐metal complexes with high levels of chemo‐ and regioselectivity . Most remarkable is the pioneering work of Wilke and coworkers who developed a Ni‐based catalyst system for the enantioselective hydrovinylation of 1,3‐cyclooctadiene (70 % ee ) and styrene (95 % ee ) employing a complex bis‐azaphospholene ligand.…”

Section: Methodsmentioning

confidence: 99%

Low‐Pressure Cobalt‐Catalyzed Enantioselective Hydrovinylation of Vinylarenes

Movahhed

Westphal

Dindaroğlu

et al. 2016

Chemistry A European J

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An efficient and practical protocol for the enantioselective cobalt-catalyzed hydrovinylation of vinylarenes with ethylene at low (1.2 bar) pressure has been developed. As precatalysts, stable [L2 CoCl2 ] complexes are employed that are activated in situ with Et2 AlCl. A modular chiral TADDOL-derived phosphine-phosphite ligand was identified that allows the conversion of a broad spectrum of substrates, including heterocyclic vinylarenes and vinylferrocene, to smoothly afford the branched products with up to 99 % ee and virtually complete regioselectivity. Even polar functional groups, such as OH, NH2 , CN, and CO2 R, are tolerated.

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Section: Methodsmentioning

confidence: 99%

Low‐Pressure Cobalt‐Catalyzed Enantioselective Hydrovinylation of Vinylarenes

Movahhed

Westphal

Dindaroğlu

et al. 2016

Chemistry A European J

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“…[26] The skipped diene product ( S )- 31 was determined to have been formed in 70% enantiomeric excess (Scheme 10). The observed complete regioselectivity of vinyl installation at the allylic position is likely a result of a relatively stable nickel/π-allyl resting state.…”

Section: Hydrovinylation Reactionsmentioning

confidence: 99%

Transition‐Metal‐Catalyzed Laboratory‐Scale Carbon–Carbon Bond‐Forming Reactions of Ethylene

2013

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Ethylene, the simplest alkene, is the most abundantly synthesized organic molecule by volume. It is readily incorporated into transitionmetal–catalyzed carbon-carbon bond-forming reactions through migratory insertions into alkylmetal intermediates. Because of its D2h symmetry, only one insertion outcome is possible. This limits byproduct formation and greatly simplifies analysis. As described within this Minireview, many carbon–carbon bond-forming reactions incorporate a molecule (or more) of ethylene at ambient pressure and temperature. In many cases, a useful substituted alkene is incorporated into the product.

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“…The use of chiral phosphanes to achieve asymmetric hydrovinylation was first mentioned in 1967,2d and a few years later Bogdanović and Wilke observed asymmetric inductions of up to 70 % ee for the coupling of 1,3‐octadiene and ethylene in the presence of (−)‐dimenthylisopropylphosphane 6…”

Section: Asymmetric Hydrovinylation Of Olefinsmentioning

confidence: 99%

Asymmetric Hydrovinylation: New Perspectives through Use of Modular Ligand Systems

Gooßen

2002

Angew. Chem. Int. Ed.

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Reaction steps in which readily accessible synthetic building blocks are regio-and enantioselectively incorporated into complex molecular frameworks without producing side products are essential for the development of modern atomeconomical syntheses. [1] Prominent examples that fulfil these requirements are asymmetric hydrogenation, hydroformylation, and Diels ± Alder reactions. In contrast, the hydrovinylation of olefins has received much less attention over the last few years, although the synthetic potential of this reaction is comparable. [2] In 1953 Ziegler et al. observed that the buildup of polyethylene on alkylaluminum compounds is suppressed when traces of nickel are present in the reaction mixture, which results in the formation of 1-butene (™nickel effect∫). [3] Wilke et al. reported in 1963 the selective dimerization of propylene using nickel ± phosphane catalysts and found that the product distribution is strongly dependent on the phosphane ligand employed. [4] When analogous reactions of mixtures of two different olefins (e.g. ethylene and norbornene) were carried out in the presence of certain nickel ± phosphane catalysts, highly selective heterocodimerization was achieved, in this case to give 2-exo-vinylnorbornane. [5] This represented the birth of a new reaction, which has come to be known as hydrovinylation: formally, a hydrogen atom and a vinyl group are added to an olefin (Scheme 1). Scheme 1. Hydrovinylation of olefins.The use of chiral phosphanes to achieve asymmetric hydrovinylation was first mentioned in 1967, [2d] and a few years later Bogdanovic ¬ and Wilke observed asymmetric inductions of up to 70 % ee for the coupling of 1,3-octadiene and ethylene in the presence of (À)-dimenthylisopropylphosphane. [6] The highpoint of these initial developments came in 1988 when Wilke et al. isolated the dimeric azaphosphole 3 from a rather complex reaction of a pinene derivative and a chiral amine. The azaphosphole 3 turned out to be an excellent ligand for asymmetric hydrovinylation. [7] For the codimerization of styrene 1 and ethylene 2 to give (R)-3-phenyl-1-butene (4) an enantiomeric excess above 95 % was observed-a record that has not been surpassed yet (Scheme 2). Scheme 2. Asymmetric hydrovinylation of styrene.A systematic tuning of the properties of ligand 3 was limited because of its complex structure. Therefore, in the following years a lot of effort was put into the development of alternative ligand systems that could be obtained more easily. Different approaches were investigated, for example palladium complexes with P-chiral ligands that gave good ee values but low yields, and nickel complexes bearing 2-diphenylphosphanyl-2'-alkoxy-1,1'-binaphthyl (™MOP∫) ligands that gave high yields but low asymmetric induction. [8,9] Significant breakthroughs in this area were not forthcoming and thus interest in hydrovinylation dwindled.Recently, Leitner et al. and RajanBabu et al. independently published new catalysts that are comparable in terms of activity and enantioselectivity to the system...

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Eine katalytisch verlaufende asymmetrische Synthese

Cited by 46 publications

References 11 publications

Low‐Pressure Cobalt‐Catalyzed Enantioselective Hydrovinylation of Vinylarenes

Low‐Pressure Cobalt‐Catalyzed Enantioselective Hydrovinylation of Vinylarenes

Transition‐Metal‐Catalyzed Laboratory‐Scale Carbon–Carbon Bond‐Forming Reactions of Ethylene

Asymmetric Hydrovinylation: New Perspectives through Use of Modular Ligand Systems

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