The Asymmetric Addition of Trimethylsilyl Cyanide to Aldehydes Catalyzed by Chiral (Salen)Titanium Complexes

Belokoń, Yuri N.; Caveda-Cepas, † Susana; Green, Brendan; Ikonnikov, N. S.; Khrustalev, Victor N.; Larichev, Vladimir; Moscalenko, Margarita A.; North, Michael; Orizu, Charles; Tararov, Vitali I.; Tasinazzo, Michela; Timofeeva, and G. I.; Yashkina, L. V.

doi:10.1021/ja984197v

Cited by 272 publications

(147 citation statements)

References 29 publications

(45 reference statements)

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“…Recently new (salen)titanium and (salen)vanadium complexes 43 (CACHy-catalysts), [56] which mediate the asymmet- ric addition of trimethylsilyl cyanide to aromatic and aliphatic aldehydes 44 [57] and ketones [58] , have been described for the preparation of substituted a-hydroxycarboxylic acids (Scheme 19, Table 1). This method has been extended to the use of potassium cyanide as a cheaper nucleophile.…”

Section: Asymmetric Càc Couplingmentioning

confidence: 99%

Industrial Methods for the Production of Optically Active Intermediates

Breuer¹,

Ditrich²,

Habicher³

et al. 2004

Angew Chem Int Ed

1,315

625

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Enantiomerically pure amino acids, amino alcohols, amines, alcohols, and epoxides play an increasingly important role as intermediates in the pharmaceutical industry and agrochemistry, where both a high degree of purity and large quantities of the compounds are required. The chemical industry has primarily relied upon established chemical methods for the synthesis of these intermediates, but is now turning more and more to enzymatic and biotechnological fermentation processes. For the industrial implementation of many transformations alternative methods are available. The advantages of the individual methods will be discussed herein and exemplified by syntheses of relevant compounds.

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Section: Asymmetric Càc Couplingmentioning

confidence: 99%

Industrial Methods for the Production of Optically Active Intermediates

Breuer¹,

Ditrich²,

Habicher³

et al. 2004

Angew Chem Int Ed

1,315

625

View full text Add to dashboard Cite

show abstract

“…More recently, North and co-workers have reported the asymmetric version of this reaction using chiral dichlorotitanium-and vanadyl-salen complexes. [175][176][177][178] A mesoporous hybrid organosilica containing a disilyl derivative of a vanadyl-salen complex has been synthesized using as silicon sources tetraethyl orthosilicate and a disilyl derivative of a vanadyl-salen complex. [179] The solid containing the vanadyl-salen complex results when both sources of silicon co-condense in the presence of cetyltrimethylammonium as structure-directing agent.…”

Section: Silica-bound Heterogeneous Catalysts For Enantioselective Cymentioning

confidence: 99%

Silica‐Bound Homogenous Catalysts as Recoverable and Reusable Catalysts in Organic Synthesis

2006

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Very frequently the most costly components in a chemical reaction are not the starting materials or the reaction products, but the catalyst. In addition to the advantages from the economic point of view, recovery and reuse of the catalyst is equally important in order to avoid wastes, so improving the greenness of the process. There is a current tendency to transform homogeneous into heterogeneous catalysis, that will even be accelerated in the near future. Starting from a successful homogeneous catalyst, one general methodology allowing its recovery and reuse is to immobilize a suitable derivative of the active catalyst on an insoluble solid support. When the catalyst does not deactivate and is sufficiently stable under the reaction conditions, the ultimate immobilization methodology is to attach covalently the catalytically active species to the support. In this contribution, after introducing some general principles describing the fundamentals of the covalent anchoring, the emphasis is placed more on giving an overview of the most important types of covalently anchored catalysts, including Brçnsted and Lewis acids, covalently anchored bases and hydrogenation complexes. Hot topics such as silica-bound organocatalysts and the application of periodic mesoporous organosilicas as heterogeneous catalysts is also covered.

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“…Trotz bedeutender Fortschritte brachten auch nichtenzymatische Katalysatoren in diesen asymmetrischen Syntheseschritten nur ca. 80 % ee, die Ausbeuten für orthosubstituierte Substrate waren gering [7,20,21] und eine Kristallisation war notwendig, um hoch enantiomerenreines 3 b zu erhalten.…”

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