Biaryl Compounds and Ligand Synthesis
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Questions and Answers

What is one major advantage of using organoborane reagents in biaryl compound preparation?

  • They enhance the color of the final product.
  • They are nontoxic and stable. (correct)
  • They are highly reactive under all conditions.
  • They do not require catalysts for reactions.
  • Which aspect significantly increases the efficacy and reactivity in the coupling reactions?

  • The temperature of the reaction.
  • The purity of phenylboronic acid.
  • The amount of aryl chloride used.
  • Electronic and steric tuning of supporting ligands. (correct)
  • What feature is crucial in the design of ligands used in the reaction processes discussed?

  • Diversity and appropriate chemical features. (correct)
  • Ability to enhance the reaction time.
  • Low cost of synthesis.
  • Compatibility with various solvents.
  • What is a noted challenge when using aryl chlorides in synthesis?

    <p>They are often unreactive.</p> Signup and view all the answers

    What was the isolated yield of ligand 1 from the reaction of dichlorophenylphosphine with chlorocyanobenzene?

    <p>68%</p> Signup and view all the answers

    What solvent was used in the synthesis of ligand 1?

    <p>Dichloromethane</p> Signup and view all the answers

    Which ligand was synthesized from dichlorophenylphosphine?

    <p>Ligand 1</p> Signup and view all the answers

    Which of the following ligands is commercially available?

    <p>Ligand 4</p> Signup and view all the answers

    Which palladium catalyst had the highest percentage yield in the results?

    <p>Pd2(dba)3</p> Signup and view all the answers

    What is the focus of the ongoing efforts mentioned in the synthesis of biaryl compounds?

    <p>Increasing substrate scope and efficiency.</p> Signup and view all the answers

    Which base was used in the synthesis of ligand 1?

    <p>Cs2CO3</p> Signup and view all the answers

    What aspect of the reaction setup is highlighted as being experimentally favorable?

    <p>The simplicity and absence of glovebox requirement.</p> Signup and view all the answers

    How long was the Pd/C reaction carried out according to the results?

    <p>16 hours</p> Signup and view all the answers

    What was the temperature condition during the synthesis of ligand 1?

    <p>Reflux temperature</p> Signup and view all the answers

    Which technique was NOT used to establish the structure of ligand 1?

    <p>Mass Spectrometry</p> Signup and view all the answers

    What was the self-coupling product discussed in the context of the reactions?

    <p>Boronic acid</p> Signup and view all the answers

    What is the duration of the reaction for entry 1?

    <p>3 hours</p> Signup and view all the answers

    Which entry has the highest product yield percentage?

    <p>Entry 1</p> Signup and view all the answers

    What is the yield of the product in entry 2?

    <p>38%</p> Signup and view all the answers

    Which of the following aryl chlorides yields a product in entry 6?

    <p>N</p> Signup and view all the answers

    What is the common solvent used in the reactions?

    <p>1,4-Dioxane</p> Signup and view all the answers

    Which catalyst is used in the reactions described?

    <p>Pd2(dba)3</p> Signup and view all the answers

    Which author is associated with work published in J. Am. Chem. Soc. in 2003?

    <p>Huang, X.</p> Signup and view all the answers

    During which entry does the reaction occur for the shortest time?

    <p>Entry 4</p> Signup and view all the answers

    What publication is associated with Aldrich Catalog from 2005-2006?

    <p>Handbook of Organopalladium Chemistry for Organic Synthesis</p> Signup and view all the answers

    Which entry corresponds to a product yield of 72%?

    <p>Entry 6</p> Signup and view all the answers

    Which journal featured an article by Viciu, M.S. in 2002?

    <p>Org. Lett.</p> Signup and view all the answers

    What is the role of Cs2CO3 in the reaction?

    <p>Base</p> Signup and view all the answers

    Which entry yields a product after 8 hours?

    <p>Entry 8</p> Signup and view all the answers

    Which of the following is a publication year for the study by Wolfe, J.P. and Buchwald, S.L.?

    <p>1997</p> Signup and view all the answers

    In which journal was the article by Grasa, G.A. published in 2001?

    <p>J. Org. Chem.</p> Signup and view all the answers

    What is the title of the edition edited by Negishi in 2002?

    <p>Handbook of Organopalladium Chemistry for Organic Synthesis</p> Signup and view all the answers

    What work is credited to Ismail, M.A. in 2005?

    <p>Bioorg. Med. Chem.</p> Signup and view all the answers

    Which patent number is referenced in the content?

    <p>JP56161310</p> Signup and view all the answers

    What is the role of Cs2CO3 in the coupling reaction?

    <p>Base</p> Signup and view all the answers

    Which of the following yields the highest product yield in this optimization?

    <p>96%</p> Signup and view all the answers

    What is the main substrate used in the optimized reaction?

    <p>Chlorocyanobenzene</p> Signup and view all the answers

    What is the effect of increasing the mol % of ligand 1?

    <p>Increases isolated yield</p> Signup and view all the answers

    How long was the reflux reaction performed to achieve optimized yields?

    <p>1 hour</p> Signup and view all the answers

    Which of the following entries produced the yield of 92%?

    <p>Entry 3</p> Signup and view all the answers

    What was the concentration of phenylboronic acid used in the reaction?

    <p>1.25 equiv</p> Signup and view all the answers

    What is the significance of using Pd2(dba)3 in this optimization?

    <p>It is the catalyst</p> Signup and view all the answers

    Study Notes

    Biaryl Compounds

    • Biaryl compounds are prepared using organoborane reagents, offering advantages such as wide functional group tolerance and nontoxicity.
    • The use of alternative bases or solvents can improve the process, but ligand design has the most significant impact on efficiency and reactivity.
    • Aryl chlorides, while cheap, are notoriously unreactive, but advancements in Pd-catalyst systems with ligands have improved the coupling process.
    • Ligands play a critical role in the coupling of aryl chlorides, hence the need for designing diverse ligands with specific features.

    Ligand 1 Synthesis

    • The synthesis of novel PN2 ligand 1 involves the reaction of dichlorophenylphosphine (5) with 2,6-dimethylmorpholin (6) in the presence of triethylamine.
    • The reaction is carried out in refluxing dichloromethane or toluene, yielding the corresponding ligand 1 with 68% yield.
    • The structure of ligand 1 was confirmed using IR, NMR, and elemental analysis.

    Ligand, Pd-catalyst, Solvent, and Base Screening

    • The coupling of chlorocyanobenzene with phenylboronic acid was optimized using the Cs2CO3/Pd2(dba)3/1 system in 1,4-dioxane.
    • The study varied the amount of ligand 1 used, along with different Pd-catalysts, to determine the optimal conditions.

    Aryl Chlorides Coupling

    • Various aryl chlorides were coupled with phenylboronic acid under optimized conditions, demonstrating the versatility of the process.
    • Heteroaryl chlorides, including those containing OEt, N, S, and MeO groups, were successfully coupled using Pd-catalyst systems in 1,4-dioxane.
    • The study explored the feasibility of coupling reactions using different aryl chlorides and phenylboronic acid.

    References

    • The research paper cited many references for further information and previous work in the area of biaryl compound synthesis and the use of ligands in palladium-catalyzed coupling reactions.
    • Included are works by prominent researchers such as Buchwald and Nolan, as well as specific publications detailing the synthesis and characterization of the ligands employed.

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    Description

    Explore the fascinating world of biaryl compounds and their synthesis through organoborane reagents. This quiz covers the preparation of novel PN2 ligands, the role of ligands in coupling processes, and the advancements in Pd-catalyst systems. Dive into the intricate details of organic chemistry and enhance your understanding!

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