Lewis Acids In Organic Synthesis Research Articles

Heterodifunctionalization of Electron-Rich Alkynes Catalyzed by in Situ Generated Silylium Ions.

Silylium ions are versatile Lewis acids in organic synthesis. While they have been well-known for the activation of σ donors, catalysis initiated by the activation of π donors remains underdeveloped, particularly for alkynes. Herein, we demonstrate an example of silylium-catalyzed alkyne heterodifunctionalization. The silylium ion generated in situ from HNTf2 and the silyl reagent serve as superior catalysts in the efficient silylphosphination and silylcyanation of electron-rich alkynes with excellent regio- and stereoselectivity. The compatibility of this protocol with strongly coordinating ligands (Ph2P and CN) not only complements the metal-catalyzed systems but also expands the scope of silylium-catalyzed reactions.

Bismuth(III) compounds as catalysts in organic synthesis: A mini review

Organic synthesis is dominated by examples of catalysis by transition metal catalysts despite their limited availability, high cost (Pd, Rh, Ru) and toxicity (Pd). In this regard, there is increased interest in the use of catalysts derived from more readily available main group metals. Bismuth(III) compounds have found considerable applications in organic synthesis since the 1990s owing to their remarkably nontoxic nature, relatively low cost, and non-corrosive nature. This review summarizes the applications of bismuth(III) salts as Lewis acids in organic synthesis. To avoid overlap with previous reviews, only articles from 2018 to 2021 are included.

A Simple and Effective Method of Determining Lewis Acidity by Using Fluorescence

Summary The strength of a Lewis acid is an important parameter in establishing its utility for practical applications. Here, we report a universal fluorescence-based method for accurately determining the strength of a range of Lewis acids. Utilizing a fluorescent dithienophosphole oxide architecture, we are able to emulate the structural motif of the widely employed Gutmann-Beckett method. This allows us to precisely correlate the optical response to the strength of a Lewis acid. In comparison to commonly used methods that employ 31P NMR chemical shifts or quantum-chemical calculations, our method strongly suggests that using fluorescent Lewis acid-base adducts (FLAs) is more reliable. Moreover, our method provides a direct measure of the Lewis acidity of a given solution, independent of the Lewis base, with direct implications to the overall utility of a Lewis acid in practical applications.

Chiral Lewis Acids in Organic Synthesis

Chiral Lewis Acids in Organic Synthesis

Carbon-Halogen Bond Activation by Selenium-Based Chalcogen Bonding.

Chalcogen bonding is a little explored noncovalent interaction similar to halogen bonding. This manuscript describes the first application of selenium‐based chalcogen bond donors as Lewis acids in organic synthesis. To this end, the solvolysis of benzhydryl bromide served as a halide abstraction benchmark reaction. Chalcogen bond donors based on a bis(benzimidazolium) core provided rate accelerations relative to the background reactivity by a factor of 20–30. Several comparative experiments provide clear indications that the observed activation is due to chalcogen bonding. The performance of the chalcogen bond donors is superior to that of a related brominated halogen bond donor.

From σ- to π-Electrophilic Lewis Acids. Application to Selective Organic Transformations

Computed enthalpies of formation for various Lewis acid complexes with representative unsaturated compounds (aldehydes, imines, alkynes, and alkenes) provide a means to evaluate the applicability of a particular catalyst in a catalytic reaction. As expected, main group Lewis acids such as BX3 show much stronger complexes with heteroatoms than with carbon-carbon multiple bonds (sigma-electrophilic Lewis acids). Gold(I) and copper(I) salts with non-nucleophilic anions increase the relative strength of coordination to the carbon-carbon multiple bonds (pi-electrophilic Lewis acids). As representative examples for the use of sigma-electrophilic Lewis acids in organic synthesis, the Lewis acid mediated allylation reactions of aldehydes and imines with allylic organometallic reagents which give the corresponding homoallyl alcohols and amines, respectively, are mentioned. The allylation method is applied for the synthesis of polycyclic ether marine natural products, such as hemibrevetoxin B, gambierol, and brevetoxin B. As representative examples for the use of pi-electrophilic Lewis acids in organic synthesis, the Zr-, Hf-, or Al-catalyzed trans-stereoselective hydro- and carbosilylation/stannylation of alkynes is mentioned. This method is extended to sigma-pi chelation controlled reduction and allylation of certain alkynylaldehydes. Gold- and copper-catalyzed benzannulation of ortho-alkynylaldehydes (and ketones) with alkynes (and alkenes) is discovered, which proceeds through the reverse electron demand Diels-Alder type [4+2] cycloaddition catalyzed by the pi-electrophilic Lewis acids. This reaction is applied for the short synthesis of (+)-ochromycinone. Palladium and platinum catalysts act as a sigma- and/or pi-electrophilic catalyst depending on substrates and reaction conditions.

Recent Advances in Silver‐Catalyzed Nitrene, Carbene, and Silylene‐Transfer Reactions

AbstractSilver salts are commonly used as Lewis acids in organic synthesis. Silver complexes can also exhibit strong oxidation power due to their high oxidation potentials. This review features the recent development of nitrene, carbene and silylene‐transfer reactions catalyzed by silver complexes. Interesting activity was observed in several reactions highlighting the unique redox chemistry of silver. A disilver(I) catalyst was shown to mediate efficient aziridination of simple olefins, intramolecular amidation of saturated C–H bonds and imination of sulfoxides with high regio‐ and stereoselectivity. Silver compounds also catalyze intermolecular carbene insertion into carbon–halogen bonds, carbon–hydrogen bonds, and aromatic systems. In addition, simple silver salts were found to mediate silylene‐transfer reactions to different olefins and alkynes efficiently. Future mechanistic study of these reactions and further exploration of the redox chemistry of silver could lead to more exciting discoveries.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Cationic Zirconocene‐ or Hafnocene‐Based Lewis Acids in Organic Synthesis: Glycoside—Flavonoid Analogy.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cationic zirconocene- or hafnocene-based Lewis acids in organic synthesis: glycoside–flavonoid analogy

Cationic metallocene species, generated from Cp 2MCl 2 and AgClO 4 (M=Zr, Hf), were used for the glycosylation of catechin derivative 2 , enabling a concise synthesis of a glycosyl flavonoid, astilbin ( 1 ). Further study revealed the efficiency of this Lewis acidic species for S N1-type activation of the C(4) position of catechin derivative 11 , enabling selective substitution with various nucleophiles.

Copper Lewis Acids in Organic Synthesis

AbstractFor Abstract see ChemInform Abstract in Full Text.

Book Review: Lewis Acids in Organic Synthesis. Vol. 1 + 2. Edited by Hisashi Yamamoto.

Book Review: Lewis Acids in Organic Synthesis. Vol. 1 + 2. Edited by Hisashi Yamamoto.

Book Review: Lewis Acids in Organic Synthesis. Vol. 1 + 2. Edited by Hisashi Yamamoto.

Angewandte Chemie International EditionVolume 40, Issue 14 p. 2717-2717 Book Review Book Review: Lewis Acids in Organic Synthesis. Vol. 1 + 2. Edited by Hisashi Yamamoto. Andreas Gansäuer, Andreas Gansäuer Kekulé -Institut für Organische Chemie und Biochemie Universität Bonn (Germany)Search for more papers by this author Andreas Gansäuer, Andreas Gansäuer Kekulé -Institut für Organische Chemie und Biochemie Universität Bonn (Germany)Search for more papers by this author First published: 10 July 2001 https://doi.org/10.1002/1521-3773(20010716)40:14<2717::AID-ANIE11112717>3.0.CO;2-YCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume40, Issue14July 16, 2001Pages 2717-2717 RelatedInformation

Lewis Acids in Organic Synthesis. By Yamamoto, Hisashi

The use of Lewis acids in organic synthesis, especially in catalysis is one of the most rapidly developing fields in synthetic organic chemistry.[...]

ChemInform Abstract: Zr‐ and Hf‐Centered Lewis Acids in Organic Synthesis

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Aldehydes vs Aldimines. Unprecedented Aldimine-Selective Nucleophilic Additions in the Coexistence of Aldehydes Using a Lanthanide Salt as a Lewis Acid Catalyst

It is well-recognized that aldimines are less reactive than aldehydes toward nucleophilic additions. In this paper, an unprecedented change in the reactivity is described: preferential reactions of aldimines over aldehydes in nucleophilic additions using a lanthanide salt as a Lewis acid catalyst. In the presence of a catalytic amount of ytterbium triflate (Yb(OTf)3), only aldimines reacted with silyl enol ethers, ketene silyl acetals, allyltributylstannane, or cyanotrimethylsilane to afford the corresponding adducts in high yields, even in the coexistence of aldehydes. Selective formation of an aldimine−Yb(OTf)3 complex rather than an aldehyde−Yb(OTf)3 complex was indicated by 13C NMR analyses. While this report demonstrates the effective use of Lewis acids in organic synthesis, the basic idea of changing reactivity as shown here will be widely applied to many other nucleophilic additions.

Polymer‐bonded Lewis acids in organic synthesis: Reduction of aldehydes, ketones and esters by polymer‐bonded aluminium hydride

Fixation d'hydrure sur une resine Amberlite IRA 93, (copolymere styrene-divinylbenzene fonctionnalise par des groupes amino tertiaires)

ChemInform Abstract: Lewis Acids in Organic Synthesis. Approach to a Selection Strategy for Screening Experiments

ChemInformVolume 18, Issue 2 Preparative Organic Chemistry ChemInform Abstract: Lewis Acids in Organic Synthesis. Approach to a Selection Strategy for Screening Experiments R. CARLSON, R. CARLSON Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorT. LUNDSTEDT, T. LUNDSTEDT Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorAA. NORDAHL, AA. NORDAHL Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorM. PROCHAZKA, M. PROCHAZKA Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this author R. CARLSON, R. CARLSON Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorT. LUNDSTEDT, T. LUNDSTEDT Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorAA. NORDAHL, AA. NORDAHL Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this authorM. PROCHAZKA, M. PROCHAZKA Dep. Org. Chem., Univ. Umea, S-901 87 Umea, Swed.Search for more papers by this author First published: January 13, 1987 https://doi.org/10.1002/chin.198702082Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue2January 13, 1987 RelatedInformation

Lewis Acids in Organic Synthesis. Approach to a Selection Strategy for Screening Experiments.

La strategie est demontree a partir des etudes experimentales de trois reactions catalysees par un acide de Lewis: alkylation d'enol ether silyle, addition Diels Alder et acylation Friedel et Crafts

Polymer-Bonded Lewis Acids in Organic Synthesis: Conversion of Carboxylic Acids into Acyl Chlorides and of Alcohols into Alkyl Chlorides or Bromides by Polymer-Bonded Phosphorus Reagents

Polymer-Bonded Lewis Acids in Organic Synthesis: Conversion of Carboxylic Acids into Acyl Chlorides and of Alcohols into Alkyl Chlorides or Bromides by Polymer-Bonded Phosphorus Reagents

Trialkylsilyl Perfluoroalkanesulfonates: Highly Reactive Silylating Agents and Lewis Acids in Organic Synthesis

Trialkylsilyl Perfluoroalkanesulfonates: Highly Reactive Silylating Agents and Lewis Acids in Organic Synthesis