Development of Chiral Catalysts for <scp>M</scp>ukaiyama Aldol Reactions in Aqueous Media

Kitanosono, Taku; Kobayashi, Shū

doi:10.1002/tcr.201300040

Cited by 16 publications

(7 citation statements)

References 86 publications

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“…The catalytic ability of Fe(II) and Fe(III) was also compared; the reaction with Fe(III) gives rise to very low yield (15%) and poor enantioselectivity (1% ee) . The diastereoselectivity of the reaction is however independent of the oxidation state of Fe . Ollevier et al also reported a similar trend for the Mukaiyama aldol reaction catalyzed by Fe(III) perchlorate system (25% yield and 52% ee) …”

Section: Introductionmentioning

confidence: 66%

“…Kitanosono et al have studied the ESI-MS spectra under the reaction conditions, and several Fe(II) complexes, such as [(L1)Fe(OTf)] + and [(L1)Fe(DME) (OTf)] + , were observed. The catalytic ability of Fe(II) and Fe(III) was also compared; the reaction with Fe(III) gives rise to very low yield (15%) and poor enantioselectivity (1% ee) . The diastereoselectivity of the reaction is however independent of the oxidation state of Fe .…”

Section: Introductionmentioning

confidence: 84%

“…The Kobayashi modification to the Mukaiyam aldol reaction, however, utilizes Lewis acids under hydrous condition. − For instance, rare earth trications and several dicationic transition metals, such as Fe, Cu, Zn, Cd, and Pd, are active catalysts in aqueous media . Asymmetric versions of the Mukaiyama aldol reactions have also been achieved in aqueous media using chiral catalysts. − One of the successful catalytic systems is Fe(II) with the Bolm’s ligand (L1) as shown in Scheme . , Relatively high enantioselectivity is achieved for a number of aromatic and nonaromatic aldehydes by using the Fe(II) catalyst. The ligand L1 has been used for aqueous asymmetric reactions, such as hydromethylation reactions, − ring-opening reactions, , and Nazarov cyclizations .…”

Section: Introductionmentioning

confidence: 99%

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The Mechanism of Iron(II)-Catalyzed Asymmetric Mukaiyama Aldol Reaction in Aqueous Media: Density Functional Theory and Artificial Force-Induced Reaction Study

et al. 2015

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Density functional theory (DFT), combined with the artificial force-induced reaction (AFIR) method, is used to establish the mechanism of the aqueous Mukaiyama aldol reactions catalyzed by a chiral Fe(II) complex. On the bases of the calculations, we identified several thermodynamically stable six- or seven-coordinate complexes in the solution, where the high-spin quintet state is the ground state. Among them, the active intermediates for the selectivity-determining outer-sphere carbon-carbon bond formation are proposed. The multicomponent artificial force-induced reaction (MC-AFIR) method found key transition states for the carbon-carbon bond formation, and explained the enantioselectivity and diastereoselectivity. The overall mechanism consists of the coordination of the aldehyde, carbon-carbon bond formation, the rate-determining proton transfer from water to aldehyde, and dissociation of trimethylsilyl group. The calculated full catalytic cycle is consistent with the experiments. This study provides important mechanistic insights for the transition metal catalyzed Mukaiyama aldol reaction in aqueous media.

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Section: Introductionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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The Mechanism of Iron(II)-Catalyzed Asymmetric Mukaiyama Aldol Reaction in Aqueous Media: Density Functional Theory and Artificial Force-Induced Reaction Study

et al. 2015

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“…We hypothesized that the addition of an organic acid might catalyze the enamine formation more effectively, 32–34 so we added chloroacetic acid (10 mol%) (Table 1, entries 13–18). We observed the best results when chloroacetic acid (10 mol%) and 10 equivalents of water are added (Table 1, entries 19–24), enhancing yields (83%–98%) and improving enantioselectivities (73%–90%).…”

Section: Resultsmentioning

confidence: 99%

Homochiral bifunctional L‐prolinamide‐ and L‐bis‐prolinamide‐catalyzed asymmetric aldol reactions performed in wet solvent‐free conditions

et al. 2020

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In this study, the novel bifunctional homochiral thiourea-L-prolinamides 1-4, tertiary amino-L-prolinamide 5, and bis-L-prolinamides 6 and 7 were prepared from enantiomerically pure (11R,12R)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene 8 and (11S,12S)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene ent-8. Highly enantioselective and diastereoselective aldolic intermolecular reactions (up to 95% enantiomeric excess, 93:7 anti/syn) between aliphatic ketones (20 equiv) and a range of aromatic aldehydes (1 equiv) were successfully carried out in the presence of water (10 equiv) and monochloroacetic acid (10 mol%), solvent-free conditions, at room temperature over 24 h using organocatalysts 1-7 (5 mol%). Stereoselective induction using density functional theory-based methods was consistent with the experimental data.

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“…Fe is an abundant, inexpensive, and nontoxic transition metal, and therefore, the development of Fe-based complexes for efficient and highly selective carbon–carbon bond formation reactions becomes critical. In this direction, the Mukaiyama aldol reaction is very useful. − We used DFT and AFIR methods to understand the mechanism and the selectivity of the aqueous Mukaiyama aldol reaction catalyzed by an Fe-based chiral complex (Figure a) …”

Section: Transition Metal Catalysismentioning

confidence: 99%

Computational Catalysis Using the Artificial Force Induced Reaction Method

2016

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The artificial force induced reaction (AFIR) method in the global reaction route mapping (GRRM) strategy is an automatic approach to explore all important reaction paths of complex reactions. Most traditional methods in computational catalysis require guess reaction paths. On the other hand, the AFIR approach locates local minima (LMs) and transition states (TSs) of reaction paths without a guess, and therefore finds unanticipated as well as anticipated reaction paths. The AFIR method has been applied for multicomponent organic reactions, such as the aldol reaction, Passerini reaction, Biginelli reaction, and phase-transfer catalysis. In the presence of several reactants, many equilibrium structures are possible, leading to a number of reaction pathways. The AFIR method in the GRRM strategy determines all of the important equilibrium structures and subsequent reaction paths systematically. As the AFIR search is fully automatic, exhaustive trial-and-error and guess-and-check processes by the user can be eliminated. At the same time, the AFIR search is systematic, and therefore a more accurate and comprehensive description of the reaction mechanism can be determined. The AFIR method has been used for the study of full catalytic cycles and reaction steps in transition metal catalysis, such as cobalt-catalyzed hydroformylation and iron-catalyzed carbon-carbon bond formation reactions in aqueous media. Some AFIR applications have targeted the selectivity-determining step of transition-metal-catalyzed asymmetric reactions, including stereoselective water-tolerant lanthanide Lewis acid-catalyzed Mukaiyama aldol reactions. In terms of establishing the selectivity of a reaction, systematic sampling of the transition states is critical. In this direction, AFIR is very useful for performing a systematic and automatic determination of TSs. In the presence of a comprehensive description of the transition states, the selectivity of the reaction can be calculated more accurately. For relatively large molecular systems, the computational cost of AFIR searches can be reduced by using the ONIOM(QM:QM) or ONIOM(QM:MM) methods. In common practice, density functional theory (DFT) with a relatively small basis set is used for the high-level calculation, while a semiempirical approach or a force field description is used for the low-level calculation. After approximate LMs and TSs are determined, standard computational methods (e.g., DFT with a large basis set) are used for the full molecular system to determine the true LMs and TSs and to rationalize the reaction mechanism and selectivity of the catalytic reaction. The examples in this Account evidence that the AFIR method is a powerful approach for accurate prediction of the reaction mechanisms and selectivities of complex catalytic reactions. Therefore, the AFIR approach in the GRRM strategy is very useful for computational catalysis.

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Development of Chiral Catalysts for Mukaiyama Aldol Reactions in Aqueous Media

Cited by 16 publications

References 86 publications

The Mechanism of Iron(II)-Catalyzed Asymmetric Mukaiyama Aldol Reaction in Aqueous Media: Density Functional Theory and Artificial Force-Induced Reaction Study

The Mechanism of Iron(II)-Catalyzed Asymmetric Mukaiyama Aldol Reaction in Aqueous Media: Density Functional Theory and Artificial Force-Induced Reaction Study

Homochiral bifunctional L‐prolinamide‐ and L‐bis‐prolinamide‐catalyzed asymmetric aldol reactions performed in wet solvent‐free conditions

Computational Catalysis Using the Artificial Force Induced Reaction Method

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