Entstehung von P-Ylid aus Triphenylphosphin und Acrylsäurederivaten

Oda, Ryohei; Kawabata, Takashi; Tanimoto, Shigeo

doi:10.1016/0040-4039(64)83110-5

Cited by 49 publications

(31 citation statements)

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“…Dysprosium(III), ytterbium(III), and zirconium(IV) isopropoxides all gave product in 16% ee (entries 3 -5). Nd(O-i-Pr) 3 afforded 2a in 25% ee (entry 6) and Y(O-i-Pr) 3 gave the best enantioselectivity observed (31% ee, entry 7). The reduced rates of these catalysts may be a result of the reduced amount of catalytic Lewis base, PEt 3 , available for Michael addition to cyclohexenone through a Lewis acid/Lewis base interaction.…”

Section: Resultsmentioning

confidence: 93%

“…The reduced rates of these catalysts may be a result of the reduced amount of catalytic Lewis base, PEt 3 , available for Michael addition to cyclohexenone through a Lewis acid/Lewis base interaction. Using enantioselectivity as the determining factor, we chose Y(O-i-Pr) 3 for our development of a Lewis acid-mediated asymmetric MBH reaction. Although enantioselectivity guided our future studies, the metal alkoxide-catalyzed process generally gave reduced yields in comparison to the Brønsted acid-catalyzed reaction.…”

Section: Resultsmentioning

confidence: 99%

“…A nucleophilic phosphine-mediated coupling between an electrophilic alkene and an aldehyde was described by Oda and co-workers in 1964. [3] They reported the combination of triphenylphosphine and acrylonitrile for in situ formation of an ylide that would undergo a Wittig reaction with benzaldehyde. Although the reaction resulted in the formation of the corresponding olefin, the mechanism required the formation of the zwitterionic intermediate from the conjugate addition of triphenylphosphine with the acrylate or acrylonitrile.…”

Section: Introductionmentioning

confidence: 99%

“…This result was later developed into an asymmetric catalytic Baylis-Hillman reaction by Chen and co-workers. [10] Chen found that the ethylenediimine ligand derived from (þ)-ketopinic acid was a good chiral ligand for the La(OTf) 3 -catalyzed Baylis-Hillman reaction. This catalytic system was determined to be highly dependent on the nature of the acrylate and aldehyde, and the highest enantioselectivities were obtained from electron-rich aldehydes such as 4-methoxybenzaldehyde.…”

Section: Introductionmentioning

confidence: 99%

“…[9] The Lewis acids that were employed in this example were lanthanide triflates. The end result was a reaction that used a catalytic amount of La(OTf) 3 and triethanolamine to promote the addition of ethyl acrylate to benzaldehyde with a 40-fold increase in rate over the parent reaction. This result was later developed into an asymmetric catalytic Baylis-Hillman reaction by Chen and co-workers.…”

Section: Introductionmentioning

confidence: 99%

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The Development of the Asymmetric Morita—Baylis—Hillman Reaction Catalyzed by Chiral Brønsted Acids

et al. 2004

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This report describes the development of a chiral Brønsted acid-catalyzed asymmetric MoritaBaylis À Hillman (MBH) reaction of cyclohexenone with aldehydes. During the course of our studies on chiral Lewis acid-promoted MBH reactions, we discovered that chiral binaphthol-derived Brønsted acids serve as promoters of the asymmetric MBH reaction. We propose that the phosphonium enolate of cyclohexenone is stabilized via hydrogen-bonding with the binaphthol-derived Brønsted acid, creating a chiral nucleophile. A practical and efficient set of conditions was developed using stoichiometric PEt 3 as the nucleophilic promoter and catalytic amounts of a binaphthol-derived Brønsted acid to effect the reaction of cyclohexenone with various aliphatic and aromatic aldehydes in good yields and enantiomeric excesses (up to 96% ee).

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Development of the Asymmetric Morita—Baylis—Hillman Reaction Catalyzed by Chiral Brønsted Acids

et al. 2004

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The Catalyzed α‐Hydroxyalkylation and α‐Aminoalkylation of Activated Olefins (The Morita—Baylis—Hillman Reaction)

1997

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In a patent application published in 1972, Baylis and Hillman reported the reaction of acetaldehyde with ethyl acrylate and acrylonitrile in the presence of catalytic amounts of 1,4‐diazabicyclo[2.2.2]octane to give the α‐hydroxyethylated products in good yields. No structure proof was given. The assignment eventually was shown to be correct, but since the initial disclosure was not followed by a journal publication, this remarkably simple, atom‐efficient, and useful reaction was ignored for a number of years, and it has been only fairly recently that its potential has begun to be explored. The transformation is now commonly referred to as the Baylis–Hillman reaction. This is unfortunate because credit for its invention clearly belongs to Morita, who five years earlier, in patents and a brief paper reported the same reaction with the exception that tertiary phosphines were used as the catalysts; he also proposed the currently accepted mechanism. Baylis and Hillman made reference to Morita's work in their patent application. It is true that tertiary amines in general are cheaper, less toxic, and more readily removed than tertiary phosphines. However, the latter sometimes give higher yields in shorter reaction times, and there are a number of examples where they are the only useful catalysts. The DABCO‐catalyzed reaction is slow, and reaction times at room temperature of days or even weeks are common. Attempts to remedy this situation by use of other amine catalysts, change of reaction temperature, high pressure, or microwave irradiation have been partially successful. Activated olefins other than acrylonitrile and acrylic esters that have now been shown to undergo the reaction include α,β‐unsaturated aldehydes and ketones, vinyl sulfoxides, vinyl sulfones, vinylsulfonates, and vinylphosphonates. β‐Substituted activated olefins do not normally react. Among electrophiles other than aldehydes, unactivated ketones undergo the Morita–Baylis–Hillman reaction only under high pressure, but activation such as in α‐halo ketones, α‐keto esters, α‐keto lactones, and nonenolizable α‐diketones often produces very reactive substrates. Imines also can be employed, provided they carry a sufficiently electronegative group on nitrogen. This chapter covers catalyzed α‐hydroxyalkylations and α‐aminoalkylations of activated olefins. Transition metal catalyzed reactions of this type, are also included even though they proceed by a different mechanism. Transformations that require stoichiometric amounts of reagents or more than one step are summarized in the section on Comparison With Other Methods but are not included in the Tabular Survey. The Morita–Baylis–Hillman reaction has been reviewed before.

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Introduction of COOH groups by carbonyl olefination

Bergel'son¹,

Shemyakin²

1969

Carboxylic Acids and Esters (1969)

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Entstehung von P-Ylid aus Triphenylphosphin und Acrylsäurederivaten

Cited by 49 publications

References 1 publication

The Development of the Asymmetric Morita—Baylis—Hillman Reaction Catalyzed by Chiral Brønsted Acids

The Development of the Asymmetric Morita—Baylis—Hillman Reaction Catalyzed by Chiral Brønsted Acids

The Catalyzed α‐Hydroxyalkylation and α‐Aminoalkylation of Activated Olefins (The Morita—Baylis—Hillman Reaction)

Introduction of COOH groups by carbonyl olefination

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