Stereo-Differentiating Reactions

Izumi, Yoshiharu; Tai, Akira

doi:10.1016/b978-0-12-377850-5.50008-8

Cited by 62 publications

(53 citation statements)

References 127 publications

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“…The authors suggested the participation of dimeric or oligomeric 10/Zn complexes in the catalytic cycle, in analogy with the previously detected dimeric complexes of Ti(OiPr) 4 with 13 (see Section 3.5).…”

Section: Addition Of Dialkylzinc Reagents To Aldehydessupporting

confidence: 73%

“…In later studies, several research groups used nonlinear correlations between the ee values of the product and the ligand (3)(4)(5) to support the formation of dimeric species in related reactions. [28][29][30][31] Walsh and co-workers…”

Section: Addition Of Dialkylzinc Reagents To Aldehydesmentioning

confidence: 99%

“…The calculation of the enantiomeric excess of the product (ee max ) for an enantiopure auxiliary can easily be done if one assumes that the enantiomers of the auxiliary (in the reagent or the catalyst) act independently. [4,5] The proportionality between ee aux and ee prod in Equation (1) allows the ee max value to be calculated (ee values between 0 and 1).…”

Section: Introductionmentioning

confidence: 99%

“…Subsequent studies using H 8 -binol revealed similar NLEs. [42] rac-H 8 -Binol and one equivalent of Ti(OiPr) 4 resulted in the formation of meso-18, as characterized by single-crystal analysis. The meso dimers were found to be in equilibria with the corresponding homochiral dimers in solution.…”

mentioning

confidence: 98%

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Nonlinear Effects in Asymmetric Catalysis

Satyanarayana¹,

Abraham²,

Kagan³

2008

Angew Chem Int Ed

491

273

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There is a need for the preparation of enantiomerically pure compounds for various applications. An efficient approach to achieve this goal is asymmetric catalysis. The chiral catalyst is usually prepared from a chiral auxiliary, which itself is derived from a natural product or by resolution of a racemic precursor. The use of non-enantiopure chiral auxiliaries in asymmetric catalysis seems unattractive to preparative chemists, since the anticipated enantiomeric excess (ee) of the reaction product should be proportional to the ee value of the chiral auxiliary (linearity). In fact, some deviation from linearity may arise. Such nonlinear effects can be rich in mechanistic information and can be synthetically useful (asymmetric amplification). This Review documents the advances made during the last decade in the use of nonlinear effects in the area of organometallic and organic catalysis.

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Section: Addition Of Dialkylzinc Reagents To Aldehydessupporting

confidence: 73%

Section: Addition Of Dialkylzinc Reagents To Aldehydesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 98%

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Nonlinear Effects in Asymmetric Catalysis

Satyanarayana¹,

Abraham²,

Kagan³

2008

Angew Chem Int Ed

491

273

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“…For that purpose the only assumption required is that mixtures of various amounts of the enantiomeric auxiliaries will provide, in the same relative amounts, two asymmetric syntheses with identical rate constants, but giving products of opposite absolute configurations. The general validity of Equation 1 has been questioned by Izumi and Tai [19]. In 1986, we demonstrated with Prof. C. Agami for the first time that deviations from Equation 1 may indeed occur in asymmetric catalysis [20].…”

Section: Enantioimpure Auxiliaries In Asymmetric Catalysismentioning

confidence: 84%

Nonlinear Effects in Enantioselective Organometallic Catalysis

Kagan

2007

Oil & Gas Science and Technology - Rev. IFP

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*Dedicated to Yves Chauvin for his outstanding contributions to catalysis Ce manuscrit est dédié à Yves Chauvin pour ses contributions exceptionnelles à la catalyse Résumé -Effets nonlinéaires dans la catalyse organométallique énantiosélective -L'historique de la catalyse organométallique énantiosélective est rappelé en introduction. Les problèmes liés à l'emploi d'auxiliaires chiraux énantioimpurs sont discutés, les effets nonlinéaires sont définis et des modèles mathématiques simples sont présentés. De nombreux exemples d'effets nonlinéaires positifs ou négatifs sont maintenant connus, certains sont mentionnés. Les effets nonlinéaires sont utiles pour aborder des mécanismes réactionnels. L'amplification asymétrique peut avoir des applications en catalyse, en permettant d'utiliser un ligand qui n'est pas énantiopur. Abstract -Nonlinear Effects in Enantioselective Organometallic

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Chiral Media for Asymmetric Solvent Inductions. ( S,S )‐( + )‐1,4‐Bis(dimethylamino)‐2,3‐dimethoxybutane from ( R,R )‐( + )‐Diethyl Tartrate

et al. 2003

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Chiral media for asymmetric solvent inductions. ( S,S )‐( + )‐1,4‐Bis(dimethylamino)‐2,3‐dimethoxybutane from ( R,R )‐( + )‐diethyl tartrate intermediate: (R,R)‐( + )‐N,N,N′,N′‐Tetramethyltartaric acid diamide reactant: 450 mL (7 mol) of liquid, anhydrous, cold (− 78°C) dimethylamine intermediate: (R,R)‐( + )‐2,3‐Dimethoxy‐N,N,N′,N′‐tetramethylsuccinic acid diamide product: (S,S)‐( + )‐1,4‐Bis (dimethylamino)‐2,3‐dimethoxybutane (DDB) reactant: (R,R)‐( + )‐diethyl tartrate reactant: (R,R)‐( + )‐tartaric acid (Firma Benckiser, D‐Ludwigshafen, or Firma Boehringer, D‐Ingelheim)

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Stereo-Differentiating Reactions

Cited by 62 publications

References 127 publications

Nonlinear Effects in Asymmetric Catalysis

Nonlinear Effects in Asymmetric Catalysis

Nonlinear Effects in Enantioselective Organometallic Catalysis

Chiral Media for Asymmetric Solvent Inductions. ( S,S )‐( + )‐1,4‐Bis(dimethylamino)‐2,3‐dimethoxybutane from ( R,R )‐( + )‐Diethyl Tartrate

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