Direct Organocatalytic Aldol Reactions in Buffered Aqueous Media
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Questions and Answers

What is the focus of the article?

  • Direct organocatalytic aldol reactions (correct)
  • Prebiotic route to sugars
  • Stereoselective construction
  • Enzyme mechanism in nature

    • What is the significance of the aldol reaction in nature?

  • It only occurs in aqueous media
  • It is a key carbon–carbon bond-forming reaction (correct)
  • It produces absolute stereocontrol
  • It is exclusively catalyzed by enzymes

    • What do Class I aldolases utilize to catalyze the reaction in nature?

  • Organocatalysts
  • Zinc cofactor
  • Enamine mechanism (correct)
  • Acidic media

    • Why have the features of nature's aldol reaction been difficult to mimic chemically?

    <p>Challenging absolute stereocontrol</p> Signup and view all the answers

    What does the article suggest about organocatalytic cross-aldol reactions?

    <p>They provide a direct route to a variety of aldols including carbohydrate derivatives</p> Signup and view all the answers

    What is the potential significance of the organocatalytic cross-aldol reactions?

    <p>They may warrant consideration as a prebiotic route to sugars</p> Signup and view all the answers

    What is the main focus of the passage?

    <p>The synthesis of polyhydroxylated products under environmentally benign reaction conditions</p> Signup and view all the answers

    What was found to be beneficial as an additive to PBS-buffer in accelerating the aldol reactions?

    <p>Sodium dodecyl sulfate (SDS)</p> Signup and view all the answers

    What did the addition of SDS to the mixture do to the uncatalyzed reaction?

    <p>Completely suppressed it</p> Signup and view all the answers

    What did the proline-catalyzed reaction in PBS/SDS completely inhibit by addition of sodium cyanide?

    <p>Aldol product formation</p> Signup and view all the answers

    What was effective for 2-butanone affording aldol adducts 3 and 4 in good yield with modest regio- and diastereoselectivity?

    <p>L-proline</p> Signup and view all the answers

    What was not a donor under L-proline catalysis?

    <p>3-pentanone</p> Signup and view all the answers

    What did the study of amines, amino acids, and small peptides as biomimetic catalysts long intrigue?

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

    What has been reported capable of catalyzing intermolecular aldol reactions with acetone as the donor under physiological conditions?

    <p>Primary and secondary amines</p> Signup and view all the answers

    What did the synthesis of polyhydroxylated products under environmentally benign reaction conditions provide for?

    <p>The synthesis of polyhydroxylated products under environmentally benign reaction conditions</p> Signup and view all the answers

    What was the focus of the study aside from synthesizing polyhydroxylated products under environmentally benign conditions?

    <p>Examining the efficiency of the approach from the perspective of its potential as a prebiotic route to carbohydrates</p> Signup and view all the answers

    What is the focus of the study mentioned in the passage?

    <p>Organocatalytic cross-aldol reactions in buffered aqueous media</p> Signup and view all the answers

    What is typically used by Class I aldolases to catalyze the aldol reaction in nature?

    <p>An enamine mechanism</p> Signup and view all the answers

    What has been particularly difficult to mimic chemically, as mentioned in the passage?

    <p>Stereocontrol in aldol products</p> Signup and view all the answers

    What did the organocatalytic cross-aldol reactions in aqueous media provide a direct route to?

    <p>Aldols including carbohydrate derivatives</p> Signup and view all the answers

    What was found to be beneficial as an additive to PBS-buffer in accelerating the aldol reactions?

    <p>SDS (sodium dodecyl sulfate)</p> Signup and view all the answers

    What was found to be beneficial as an additive to PBS-buffer in accelerating the aldol reactions?

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

    What did the proline-catalyzed reaction in PBS/SDS completely inhibit by addition of sodium cyanide?

    <p>Imine as an intermediate</p> Signup and view all the answers

    What was not a donor under L-proline catalysis?

    <p>3-pentanone</p> Signup and view all the answers

    Why have synthetically useful aldol reactions in aqueous media been rare?

    <p>Lack of enzymes and catalytic antibodies</p> Signup and view all the answers

    What did the synthesis of polyhydroxylated products under environmentally benign reaction conditions provide for?

    <p>Prebiotic route to carbohydrates</p> Signup and view all the answers

    What was effective for 2-butanone affording aldol adducts 3 and 4 in good yield with modest regio- and diastereoselectivity?

    <p>L-proline catalysis</p> Signup and view all the answers

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