Nonlinear effects in the enantioselective 1,4-conjugate addition of diethylzinc to chalcone

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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“…Hu et al [56] found a (+)-NLE in the copper-catalyzed addition of Et 2 Zn to chalcone in the presence of the bidentate P,N ligand 35 [Eq. (10)].…”

Section: Conjugate Additions To Enonesmentioning

confidence: 99%

Nonlinear Effects in Asymmetric Catalysis

Satyanarayana¹,

Abraham²,

Kagan³

2008

Angew Chem Int Ed

500

273

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“…Hu et al 56. fanden einen (+)‐NLE bei der Kupfer‐katalysierten Addition von Et 2 Zn an Chalkon unter Verwendung des zweizähnigen P,N‐Liganden 35 [Gl.…”

Section: Nichtlineare Effekte In Der Homogenen Metallorganischen Kunclassified

Nichtlineare Effekte in der asymmetrischen Katalyse

2008

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Zahlreiche Anwendungen in der Chemie erfordern die Synthese enantiomerenreiner Verbindungen. Einen effizienten Ansatz hierfür bietet die asymmetrische Katalyse. Hierbei wird der chirale Katalysator gewöhnlich aus einem chiralen Auxiliar erzeugt, das z. B. von einem Naturstoff abgeleitet wurde oder aus der Racematspaltung racemischer Vorstufen stammt. Die Verwendung nicht‐enantiomerenreiner chiraler Auxiliare in der asymmetrischen Katalyse scheint aus präparativer Sicht ungünstig, da man erwarten sollte, dass der Enantiomerenüberschuss (ee) des Reaktionsprodukts zum ee‐Wert des chiralen Auxiliars proportional ist (Linearität). Tatsächlich kann es jedoch zu Abweichungen von der Linearität kommen. Derartige nichtlineare Effekte können sehr aufschlussreich für den Mechanismus einer Reaktion sein und außerdem in der Synthesechemie genutzt werden (asymmetrische Verstärkung). Dieser Aufsatz fasst die Fortschritte der letzten zehn Jahre bei der Anwendung des nichtlinearen Effekts in der metallorganischen und organischen Katalyse zusammen.

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“…[9] NOBIN-based P,N-bidentate phosphites L G,H are highly efficient in the Cu-catalyzed enantioselective conjugate additions, and P-monodentate MOP-type compounds L I,J were shown to have good to excellent enantioselectivity in the Pd-catalyzed allylation and in the Rh-catalyzed hydrogenation. [10,11] In the last few years, we have developed a new class of highly modular diamidophosphite ligands with 1,3,2-diazaphospholidine rings that promote a wide range of catalytic asymmetric reactions. [12] It should be noted that these P*-chiral 1,3,2-diazaphos- Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Catalytic Reactions Using P‐Mono‐, P,N‐ and P,P‐Bidentate Diamidophosphites with BINOL Backbones and 1,3,2‐Diazaphospholidine Moieties: Differences in the Enantioselectivity

et al. 2010

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A new series of P*-chiral diamidophosphites with 1,3,2-diazaphospholidine rings, based on (S a )-or (R a )-BINOL and their easily accessible derivatives, has been synthesized for the first time and tested in asymmetric transition metal catalysis. Up to 99% ee was achieved in the rhodium-catalyzed asymmetric hydrogenation of functionalized olefins and in the palladium-catalyzed allylic substitution. The influence of the nature of the donor atoms and denticity on the asymmetric induction is discussed. In addition, the first example of a successful platinum-catalyzed asymmetric allylic amination (up to 86% ee) with participation of organophosphorus ligands is considered.

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Nonlinear effects in the enantioselective 1,4-conjugate addition of diethylzinc to chalcone

Cited by 17 publications

References 62 publications

Nonlinear Effects in Asymmetric Catalysis

Nonlinear Effects in Asymmetric Catalysis

Nichtlineare Effekte in der asymmetrischen Katalyse

Asymmetric Catalytic Reactions Using P‐Mono‐, P,N‐ and P,P‐Bidentate Diamidophosphites with BINOL Backbones and 1,3,2‐Diazaphospholidine Moieties: Differences in the Enantioselectivity

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Nonlinear effects in the enantioselective 1,4-conjugate addition of diethylzinc to chalcone

Cited by 17 publications

References 62 publications

Nonlinear Effects in Asymmetric Catalysis

Nonlinear Effects in Asymmetric Catalysis

Nichtlineare Effekte in der asymmetrischen Katalyse

Asymmetric Catalytic Reactions Using P*‐Mono‐, P*,N‐ and P*,P*‐Bidentate Diamidophosphites with BINOL Backbones and 1,3,2‐Diazaphospholidine Moieties: Differences in the Enantioselectivity

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Asymmetric Catalytic Reactions Using P‐Mono‐, P,N‐ and P,P‐Bidentate Diamidophosphites with BINOL Backbones and 1,3,2‐Diazaphospholidine Moieties: Differences in the Enantioselectivity