Mechanism of Enolate Transfer between Si and Cu

Bouaouli, Samira; Spielmann, Kim; Vrancken, Emmanuel; Campagne, Jean‐Marc; Gérard, Hélène

doi:10.1002/chem.201800099

Cited by 10 publications

(5 citation statements)

References 46 publications

(83 reference statements)

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“…This TMS/F exchange step has extensively been studied computationally by some of us recently, using [Cu(PH 3 ) 2 ] + as a model copper complex [17] . We demonstrated that the exchange between F and a highly conjugated enolate chain like the one used here is highly exergonic and irreversible.…”

Section: Resultsmentioning

confidence: 73%

“…This TMS/F exchange step has extensively been studied computationally by some of us recently, using [Cu(PH 3 ) 2 ] + as a model copper complex. [17] We demonstrated that the exchange between F and a highly conjugated enolate chain like the one used here is highly exergonic and irreversible. The same mechanism was recomputed here, using a "small model" of the Cu(I) • tolBINAP to replace the Cu(I) • (PH 3 ) 2 complex used previously (see computational details) and a non-substituted silyl dienolate SE (see Table 2).…”

Section: Stage 3: Addition Of the Second Equivalent Of Tbatmentioning

confidence: 73%

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Intertwined Analytical, Experimental and Theoretical Studies on the Formation and Structure of a Copper Dienolate

Lecachey

Palais

Courcy

et al. 2021

Chemistry A European J

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The reaction of a silyl dienolate, a Cu(II) salt and TBAT yielding the corresponding copper dienolate is addressed. A combined NMR and cyclic voltammetry analysis first highlight the role of TBAT in the Cu(II) to Cu(I) reduction and the structure of the precatalytic species. From these first results a second set of NMR and theoretical studies enable the determination of the structure and the mechanism of formation of the copper dienolate catalytic species. Finally, we showed that that the copper catalyst promote the E/Z scis/s-trans equilibration of the silyl dienolate precursor through a copper dienolate intermediate. All of these results unveil some peculiarities of the catalytic and asymmetric vinylogous Mukaiyama reaction.

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Section: Resultsmentioning

confidence: 73%

Section: Stage 3: Addition Of the Second Equivalent Of Tbatmentioning

confidence: 73%

Intertwined Analytical, Experimental and Theoretical Studies on the Formation and Structure of a Copper Dienolate

Lecachey

Palais

Courcy

et al. 2021

Chemistry A European J

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“…For example, in the copper(I)-catalyzed asymmetric vinylogous aldol reaction of dienolsilanes and aldehydes, the products were obtained as a mixture of (E)-form and lactone derived from (Z)-form. [5] Such a tendency was also observed in the copper(I)-catalyzed direct vinylogous aldol reaction of aldehydes and ester of but-3-enoic acid. [6] Fortunately, a one-pot strategy including vinylogous aldol reaction, Ph 2 PMe-promoted isomerization of (E)-form to (Z)-form, and intra-molecular transesterification, could be employed to afford lactone as the only product.…”

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confidence: 66%

Copper(I)‐Catalyzed Asymmetric Vinylogous Aldol‐Type Reaction of Allylazaarenes

et al. 2021

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A vinylogous aldol‐type reaction of allylazaarenes and aldehydes is disclosed that affords a series of chiral γ‐hydroxyl‐α,β‐unsaturated azaarenes in moderate to excellent yields with high to excellent regio‐ and enantioselectivities. With (R,RP)‐TANIAPHOS and (R,R)‐QUINOXP* as the ligand, the carbon‐carbon double bond in the products is generated in (E)‐form. With (R)‐DTBM‐SEGPHOS as the ligand, (Z)‐form carbon‐carbon double bond is formed in the major product. In this vinylogous reaction, aromatic, α,β‐unsaturated, and aliphatic aldehydes are competent substrates. Moreover, a variety of azaarenes, such as pyrimidine, pyridine, pyrazine, quinoline, quinoxaline, quinazoline, and benzo[d]imidazole are well‐tolerated. At last, the chiral vinylogous product is demonstrated as a suitable Michael acceptor towards CuI‐catalyzed nucleophilic addition with organomagnesium reagents.

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“…However, only a small quantity of VAR products (γ-adducts) was obtained. On the other hand, in the case of linear copper(I)–dienolates generated through transmetalation with dienolsilanes, γ-addition dominated the reaction with aldehydes, which was a catalytic asymmetric MVAR reported by Campagne group (Scheme b) . In this reaction, linear products were symbiotically produced with α,β-unsaturated δ-lactones.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Synthesis of α,β-Unsaturated δ-Lactones through Copper(I)-Catalyzed Direct Vinylogous Aldol Reaction

Zhang

Yin

2018

J. Am. Chem. Soc.

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A simple methodology for the asymmetric synthesis of chiral α,β-unsaturated δ-lactones was achieved by copper(I)-catalyzed direct vinylogous aldol reaction (DVAR) of β,γ-unsaturated esters and various aldehydes, including aromatic aldehydes, heteroaromatic aldehydes, α,β-unsaturated aldehydes, and aliphatic aldehydes. For aromatic and heteroaromatic aldehydes, a one-pot reaction consisting of DVAR, isomerization of the unsaturated carbon-carbon double bond from ( E)-form to ( Z)-form, and subsequent intramolecular transesterification was required to get the lactones in moderate to high yields with high enantioselectivity. For α,β-unsaturated and aliphatic aldehydes, the DVAR proceeded directly to afford the lactones in moderate yields with high enantioselectivity. In the DVAR, various functional groups were well tolerated. Moreover, the methodology was nicely applicable to the aldehyde group distributed in natural products, derivatives of natural product, and derivatives of drug molecules (atomoxetine and naproxen). The mechanism studies revealed that α-addition was reversible and not favored, which accounted for the excellent regioselectivity in the DVAR. The copper(I)-dienolate species generated through deprotonation was proposed to form an equilibrium with an allylcopper(I) species, which reacted with aldehydes to afford the DVAR products through a catalytic asymmetric allylation of aldehydes. Finally, the robustness of the present reaction was demonstrated by a gram-scale reaction, and the utility of the present methodology was showcased by the formal asymmetric synthesis of ezetimibe and fostriecin.

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Mechanism of Enolate Transfer between Si and Cu

Cited by 10 publications

References 46 publications

Intertwined Analytical, Experimental and Theoretical Studies on the Formation and Structure of a Copper Dienolate

Intertwined Analytical, Experimental and Theoretical Studies on the Formation and Structure of a Copper Dienolate

Copper(I)‐Catalyzed Asymmetric Vinylogous Aldol‐Type Reaction of Allylazaarenes

Asymmetric Synthesis of α,β-Unsaturated δ-Lactones through Copper(I)-Catalyzed Direct Vinylogous Aldol Reaction

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