3-Stannylcyclobutenediones as nucleophilic cyclobutenedione equivalents. Synthesis of substituted cyclobutenediones and cyclobutenedione monoacetals and the beneficial effect of catalytic copper iodide on the Stille reaction

Liebeskind, L. S.; Fengl, R. W.

doi:10.1021/jo00306a012

Cited by 325 publications

(126 citation statements)

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“…The technology developed by Liebeskind [132] involves the treatment of 3,4-di-ethoxycyclobutenediones with the silylstannane, [n-Bu3SnSiMe3] under catalytic conditions [tetra-n-butylammonium cyanide] furnished 3-ethoxy-4-(tri-n-butylstannyl)cyclobutenedione in 65% yield ( Figure 36). This compound is cross-coupled with organic iodides attached to sp 2 and sp-hybridized carbon atoms, under the influence of co-catalytic palladium/Cu species, to provide 3-ethoxy-4-substituted-cyclobutenediones in excellent yields.…”

Section: Figure 35 Synthesis Of Phosphonic Acid Squaramidementioning

confidence: 99%

“…This strategy is used in the presence of the diethoxyphosphinyl group required for the synthesis of potential NMDA antagonists, as well as other functionalities [132]. Liebeskind's reagent (3-ethoxy-4(tri-n-butylstannyl)cyclobutenedione) is useful in palladium-catalysed Stille cross-coupling with various alkyl and aryl iodides.…”

Section: Figure 35 Synthesis Of Phosphonic Acid Squaramidementioning

confidence: 99%

“…This novel free radical procedure provides an additional method for incorporation of functionalized alkyl groups into the cyclobutenedione moiety [132]. …”

Section: Figure 35 Synthesis Of Phosphonic Acid Squaramidementioning

confidence: 99%

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Squaryl Molecular Metaphors – Application to Rational Drug Design and Imaging Agents

Kitson¹

2017

J Diagn Imaging Ther

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Molecular Metaphors is the application of squaryl building blocks towards creative functional group chemistry to produce lead compounds and imaging agents. This strategy is applied to rational drug design and to various imaging agents that would normally contain conventional functional group chemistry. These, include carboxylic acids, α-amino acids, peptide bonds and phosphonates. Moreover, the squaryl metaphor is a precursor to complex organic molecules involving functional group interchange (FGI) and rearrangements. This article discusses the application of these metaphors in the area of neurochemistry, especially NMDA receptors. An important area of drug design is the inhibition of angiotensin II enzyme by the use of losartan. This commercial drug contains a tetrazole moiety that can be modified using the squaryl group to give a semisquarate derivative. These concepts can extend to the semisquarate of ibuprofen. Moreover, a discussion on peptidomimetics regarding the substitution of the peptide bond for squaramide allows for a change in the biological properties due to modification at the peptide bond. Furthermore, the topic on how squaryl metaphors can be exploited primarily by the central 1,3-hydroxyamide sequence to the generation of a novel class of HIV protease inhibitors. Also, squaryl metaphors can be used to develop potential inhibitors of glutathione and novel anti-migraine drugs. The discussion continues on the design of anticancer drugs: in particular, a novel class of metalloproteases, including phosphonates for semisquaramides, leading to squaryl nucleosides. This review concludes with the application of squaryl metaphors in the design of positron emission tomography (PET) and magnetic resonance imaging (MRI) agents towards theranostics. describe the ability of individual functional chemical groups to mimic other moieties [2,3]. KeywordsErlenmeyer rationalised these concepts and categorised isosteres into atoms, ions and molecules based on the valence level of electrons [4]. A further understanding by Friedman led to the term bioisosterism to include all atoms and molecules that fit the broadest definition of isosteres [5]. This approach was independent of whether the drug was an agonist or an antagonist towards biological activity.Moreover, Thornber applied the term bioisosterism to include subunits, groups or molecules that possess physicochemical properties of similar biological effects [6]. Finally, in 1991 Burger widened the definition of bioisosteres to include compounds or groups that possess similar molecular shapes and volumes independent of agonists or antagonists [7]. REVIEW ARTICLE Squaryl KitsonThese bioisosteres would require approximately the same distribution of electrons and give a high probability of generating comparable physical properties such as hydrophobicity [8]. Currently, bioisosterism is one of the most useful tools to the medicinal chemist in rational drug design and in particular regarding the carboxylic acid bioisosteres [9]. The carboxylic acid functional ...

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Section: Figure 35 Synthesis Of Phosphonic Acid Squaramidementioning

confidence: 99%

Section: Figure 35 Synthesis Of Phosphonic Acid Squaramidementioning

confidence: 99%

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Squaryl Molecular Metaphors – Application to Rational Drug Design and Imaging Agents

Kitson¹

2017

J Diagn Imaging Ther

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“…18 3-Stannylcyclobutenediones and stannylcyclobutenedione monoacetals undergo efficient palladium-catalysed cross-coupling reactions with organic iodides.…”

Section: (B) Modified Stille Cross-couplingmentioning

confidence: 99%

Copper(I) Iodide

Coeffard¹

2007

Synlett

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This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research Copper(I) IodideCompiled by Vincent Coeffard Vincent Coeffard was born in Nantes, France in 1981. He received his M.Sc. from the University of Nantes in 2004 and subsequently joined the research group of Prof. J.-P. Quintard to pursue his Ph.D. studies in the same university. His research interests focus on preparation, electrochemical studies and applications of enantiopure a-aminoorganostannanes in asymmetric synthesis.

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“…Liebeskind et al 70 developed a general method involving stable 3-(tri-n-butylstannyl)-3-cyclobutene-1,2-dione 70 which was readily prepared by the treatment of 3,4-diisopropoxy-3-cyclobutene-1,2-dione with n-Bu 3 SnSiMe 3 in the presence of catalytic amount of cyanide ion (Equation 11). …”

Section: Scheme 44mentioning

confidence: 99%