α,β‐Unsaturated δ‐Lactones from Copper‐Catalyzed Asymmetric Vinylogous Mukaiyama Reactions of Aldehydes: Scope and Mechanistic Insights

Bazan‐Tejeda, Belen; Bluet, Guillaume; Broustal, Garance; Campagne, Jean‐Marc

doi:10.1002/chem.200600335

Cited by 74 publications

(34 citation statements)

References 62 publications

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“…35 Furthermore, a novel synthesis of a,b-unsaturated dlactones from asymmetric VMARs was also developed by this group and resulted in one-step synthesis of natural product goniothalamin (95) (Fig. 30) 36 though there was still room for enantioselective improvement.…”

Section: Enantioselective Processesmentioning

confidence: 99%

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The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

et al. 2014

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The vinylogous Mukaiyama aldol reaction (VMAR) allows efficient access to larger segments for complex natural product synthesis, primarily polyketides, through the construction of vicinal hydroxyl and methyl groups as well as di and tri-substituted double bonds in one single operation. In this review, we will highlight stereoselective protocols that have been used in natural product synthesis and cluster them into the four groups that can be obtained from different silyl ketene acetals or enol ethers. At the beginning, an overview on different stereoselective VMARs is presented; disregarding their applications in total syntheses.

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Section: Enantioselective Processesmentioning

confidence: 99%

“…60). 20,36 Nevertheless, this catalytic cycle does not explain the enantioselectivity of this process, since the chiral copper center seems to be too distant from the prochiral aldehyde (Fig. 61).…”

Section: Diastereoselective Transformations Using Silyl Ketene Acetalsmentioning

confidence: 99%

The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

et al. 2014

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“…Our idea for the generation of the first chiral center was based on our experience in the catalytic and asymmetric vinylogous Mukaiyama reactions (CAVM, Scheme 1). [5] These types of additions have already proved to be very effective in yielding highly enantioenriched 2-alkene-1,5-diols via an α,β-unsaturated δ-lactone. [6] [a] Institut de Chimie des Substances Naturelles, We expected these diols to react with tosyl isocyanate to give the corresponding dicarbamates, which could be cyclized to 1,3-oxazinan-2-ones with 1,3-asymmetric induction (Scheme 2).…”

Section: Introductionmentioning

confidence: 98%

A Stereoselective Approach to 1,3‐Amino Alcohols Protected as Cyclic Carbamates: Kinetic vs. Thermodynamic Control

Broustal¹,

Ariza²,

Campagne³

et al. 2007

Eur J Org Chem

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International audienceDirect enantiocontrolled access to 1,3-amino alcohols protected as cyclic carbamates is described. The approach is based on the addition of a silyl dienolate to aldehydes in the presence of 10 % of Carreira's catalyst (vinylogous Mukaiyama-aldol addition). The obtained -hydroxyesters were reduced to pent-2-ene-1,5-diols, which were converted into the corresponding dicarbamates with tosyl isocyanate. Stereoselective cyclization of these dicarbamates proceeded with 1,3-asymmetric induction under either thermodynamic or kinetic control to afford enantioselectively six-membered-ring cyclic carbamates. Calculations enabled us to rationalize the observed stereoselectivit

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“…10 Such a distillation procedure may not be preferred for expensive starting esters because of their low yields. Alternatively, these reactions can be catalyzed by simple Lewis acids 11 and their complexes which can be prepared prior to the reaction.…”

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One-pot vinylogous aldol addition of β,γ-unsaturated esters under mild conditions

Akçok

Çağır

2015

New J. Chem.

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We described a one-pot vinylogous aldol addition of methyl 3-butenoate to aromatic aldehydes in the presence of silver salts and the TMSCl-TBAF mixture. The reaction can be done simply by sequentially mixing reagents in situ, and it does not require any catalyst or dienolate ether preparations prior to the reaction.Synthesis of a,b-unsaturated-d-lactones is of great importance to scientists because of their valuable antitumor, antibacterial, and antifungal activities.1,2 Vinylogous aldol addition of esters(1 or 2) to aldehydes (4) produces unsaturated esters (5) which are valuable precursors for the synthesis of 6-alkyl or 6-aryl substituted 5,6-dihydro-2H-pyran-2-one derivatives (6). 3,4 In general, vinylogous aldol addition reactions of esters (1 or 2) to aldehydes (4) are performed by a two-step procedure. In the first step, starting esters (1 or 2) should be transferred to O-silyldienolate (3) 5-9 and then purified by unreacted LDA and formed diisopropylamine by distillation before addition to aldehydes (Scheme 1). 10 Such a distillation procedure may not be preferred for expensive starting esters because of their low yields. Alternatively, these reactions can be catalyzed by simple Lewis acids 11 and their complexes which can be prepared prior to the reaction. 12 Here we report a one-pot vinylogous aldol addition of b,g-unsaturated ester (2) to aromatic aldehydes under mild conditions. The aim of the study is to prepare 1-methoxy-1-(trimethylsiloxy)-1,3-butadiene (3) in situ via the reaction of methyl 3-butenoate (2) and trimethylsilyl cation which can be simply generated by the reaction between silver salts and TMSCl. Then the addition of aldehyde would give the vinylogous aldol addition product (8). For this purpose 1-naphthaldehyde (7) was chosen as a model aromatic aldehyde for the optimization of reaction conditions (Scheme 2). Preliminary studies showed that pretreatment of starting ester 2 with silver carbonate and TMSCl for one hour followed by the addition of TBAF and 1-naphhaldehyde gave compound 8 with 39% yield. Interestingly, when the reaction was repeated in the absence of any one of the reagents, silver carbonate, TMSCl or TBAF, the reaction did not occur.To investigate the effect of choice of solvent on reaction yield, reaction was carried out in 1.0 mL of THF, toluene, NMP, and DMF. All reactions were terminated after 24 hours and products were isolated. It seems that reaction proceeds faster in DMF and gives the highest yield of 39%. When the amount of DMF was increased to 4.0 mL the yield of the reaction increased to 44% but further dilutions of reactants in 10 mL of DMF slowed down the reaction and resulted in only 28% yield (Table 1).Scheme 1 Vinylogous aldol addition products as precursors of a,bunsaturated-d-lactones.Scheme 2 One-pot vinylogous aldol addition to 1-naphthaldehyde.

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α,β‐Unsaturated δ‐Lactones from Copper‐Catalyzed Asymmetric Vinylogous Mukaiyama Reactions of Aldehydes: Scope and Mechanistic Insights

Cited by 74 publications

References 62 publications

The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

A Stereoselective Approach to 1,3‐Amino Alcohols Protected as Cyclic Carbamates: Kinetic vs. Thermodynamic Control

One-pot vinylogous aldol addition of β,γ-unsaturated esters under mild conditions

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