Palladium-catalyzed reactions of acyl chlorides with (1-alkynyl)tributylstannanes. A convenient synthesis for 1-alkynyl ketones

Logue, Marshall W.; Teng, Kelly

doi:10.1021/jo00134a010

Cited by 174 publications

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“…The previous study involved proton addition to a trimethylsilylacetylene with either another trimethylsilyl group or a tributylstannyl group at the other end, eq. [4], while in the present case addition was to a phenylacetylene with the metallic group at the other end, eq. [5].…”

Section: Reactivitymentioning

confidence: 86%

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The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

Egle¹,

Gabelica²,

Kresge³

et al. 1996

Can. J. Chem.

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Abstract:Rates of conversion of 1-(tri-11-butylstanny1)-2-phenylethyne to phenylethyne in HzO and D,O solutions of perchloric acid were found to be proportional to acid concentration, giving the hydronium ion rate constant kH+ = 1.85 x lo-' M-I s-I and the isotope effect kHJkD+ = 3.10. The magnitude of this isotope effect suggests that the reaction occurs by rate-determining hydron transfer to the substrate, producing a vinyl carbocation; this carbocation then loses its tributylstanny l group, giving phenylacetylene as the only detectable aromatic product. The hydronium ion rate constant, when compared to the rates of protonation of phenylethyne and I-(trimethylsily1)-2-phenylethyne, gives a P-stannyl stabilizing effect of FAG*= 6.6 kcal mol-I and a differential P-stannyVP-silyl effect of FAG*= 3.2 kcal mol-I. These stabilizations are very much smaller than previously reported P-stannyl effects. Possible reasons for the difference are suggested.Key words: P-stannyl effect, P-silyl effect, carbocation stabilization, protodemetalation.RCsumC : On a trouvt que les vitesses de conversion du I-(tri-n-butylstanny1)-2-phtnyltthyne en phCnylCthyne, en solutions d'acide perchlorique dans du H,O et dans du D20, est proportionnelle B la concentration d'acide; la constante de vitesse de l'ion hydronium kH+ = 1,85 x 10-2 M-' s-I et I'effet isotopique kH+lkD+ = 3,10. L'amplitude de cet effet isotopique suggkre que la reaction se produit par une ttape dtterminant la vitesse au cours de laquelle il y a transfert d'un hydron au substrat conduisant B la formation d'un carbocation vinylique; ce carbocation perd alors son groupe tributylstannyle ne donnant que du phCnylacCtyl6ne comme seul produit aromatique pouvant &tre dttecte. Lorsqu'on compare la constante de vitesse de I'ion hydronium aux vitesses de protonation du phtnyltthyne et du I-(trimCthylsily1)-2-phCnyltthyne, on en dtduit l'effet stabilisant du groupe P-stannyle, FAG'= 6,6 kcal mol-I, ainsi que la difftrence entre les effets P-stannyle et P-silyle, FAG" 3,2 kcal mol-I. Ces stabilisations sont beaucoup plus faibles que celles rapportCes antkrieurement pour les effets P-stannyles. On suggkre diverses raisons possibles pour la difference.Mots clgs : effet P-stannyle, effet P-silyle, stabilisation du carbocation, protodCmttallation. [Traduit par la rtdaction]It is well known that silyl substituents in the P-position stabilize carbocations strongly (for reviews, see ref. l), and other Group IV A metals lying below silicon in the periodic table have even more powerful effects. For example, a stannyl substituent in the P-position was found to accelerate the rate of solvolysis of a cyclohexanol ester over that of the unsubstituted substrate by a factor much in excess of 1 0 '~ (2), and the remarkably large stannyllsilyl rate ratio of lo8 was observed in the protonation of metalated acetylenes (3). We were surprised to discover, therefore, that the stannyl group in 1-(tri-rz-butylstanny1)-2-phenylethyne raises the rate of vinyl cation formation by protonation of this substance...

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Section: Reactivitymentioning

confidence: 86%

“…Materials I-(Tri-n-butylstanny1)-2-phenylethyne was prepared by treating lithium phenylacetylide with tributyltin chloride (4). All other materials were best available commercial grades.…”

Section: Methodsmentioning

confidence: 99%

The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

Egle¹,

Gabelica²,

Kresge³

et al. 1996

Can. J. Chem.

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“…[5,9] A prevalent path involves alkynyl organometallic reagents with acid chloride. [10] However,a na lternative andm ore atom-economic protocol fort he preparation of such compounds is the palladium-catalyzed direct carbonylative Sonogashira coupling reactiono fa ryl iodides with terminal alkynes in the presence of the simplest C1 unit and atom-efficient carbon monoxide.…”

Section: Introductionmentioning

confidence: 99%

Functionalized Magnetic Mesoporous Silica Nanoparticle‐Supported Palladium Catalysts for Carbonylative Sonogashira Coupling Reactions of Aryl Iodides

Natour

Abu‐Reziq

2015

ChemCatChem

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Magnetic mesoporous silica nanoparticles (MMSN) were prepared and used as a support for palladium catalysts. MMSN with a surface area of 1909 m2 g−1 were synthesized by a nanoemulsification process involving the dispersion of hydrophobic magnetite nanoparticles in chloroform in the presence of cetyltrimethylammonium bromide, followed by the addition of tetraethoxysilane and its polycondensation by a sol–gel route. The MMSN were modified with phosphine and N‐heterocyclic carbene‐based ligands, which provided coordination sites for conjugation with a palladium catalyst. These modified particles were fully characterized and employed as catalyst nanosupports. The palladium catalyst was immobilized on the surface and within the pores of MMSN and applied in copper‐free carbonylative Sonogashira coupling reactions of aryl iodides with terminal alkynes.

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“…The reaction of metal 12,13 and metalloid 14 acetylides with acyl chlorides is one common route for the preparation of ynones. Alternatively, the synthesis of ynones from acyl chloride can be achieved via two-step procedures using Weinreb amides and organolithium or Grignard reagents.…”

Section: Introductionmentioning

confidence: 99%

Metal-Free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Taylor

Bolshan

2013

Org. Lett.

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Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups and scaffolds. Traditional methods for the preparation of ynones are associated with drawbacks including harsh conditions, multiple purification steps, and the presence of unwanted byproducts. An alternative method for the straightforward preparation of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts is described herein. The adoption of organotrifluoroborate salts as an alternative to organometallic reagents for the formation of new carbon-carbon bonds has a number of advantages. Potassium organotrifluoroborate salts are shelf stable, have good functional group tolerance, low toxicity, and a wide variety are straightforward to prepare. The title reaction proceeds rapidly at ambient temperature in the presence of a Lewis acid without the exclusion of air and moisture. Fair to excellent yields may be obtained via reaction of various aryl and alkyl acid chlorides with alkynyltrifluoroborate salts in the presence of boron trichloride. Video LinkThe video component of this article can be found at

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Palladium-catalyzed reactions of acyl chlorides with (1-alkynyl)tributylstannanes. A convenient synthesis for 1-alkynyl ketones

Cited by 174 publications

References 0 publications

The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

Functionalized Magnetic Mesoporous Silica Nanoparticle‐Supported Palladium Catalysts for Carbonylative Sonogashira Coupling Reactions of Aryl Iodides

Metal-Free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

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