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Carbonyl Condensation Reactions

Carbonyl Condensation Reactions. Very General Reaction. What is needed? A Ketone or aldehyde ONE reactant must have a -Hydrogens Base (NaOH). NO α - HYDROGENS. Very General Reaction. α. α. α. α. α. α. 1. An α -carbon is the carbon directly attached to the C=O

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Carbonyl Condensation Reactions

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  1. Carbonyl Condensation Reactions

  2. Very General Reaction. • What is needed? • A Ketone or aldehyde • ONE reactant must have a-Hydrogens • Base (NaOH)

  3. NO α-HYDROGENS Very General Reaction. α α α α α α 1. An α-carbon is the carbon directly attached to the C=O 2. Hydrogens attached to these C are called α-hydrogens

  4. O - H O H O α • Aldol Condensation Reaction 2 C C H H 3 α A c e t a l d e h y d e - O O O C C C C H C H H 2 3 C H H 3 H α - H O O O H 2 O O - β H O C C C C C H C H C H C H H 2 3 H 2 3 H H A l d o l a β-hydroxy aldehyde

  5. Predict the Products • Aldol reactions

  6. O H Possible Crossed Aldols • One carbonyl has no a-hydrogens O O S l o w l y C C - H H O H a d d H C a n n o t f o r m O e n o l a t e O O H C H H

  7. O O C C H H C C H H C C 3 3 2 2 H H - d i l u . H O Practice making mixed products • Aldol reactions with O - C H C d i l u . H O 2 H + + O There are two products for each reaction

  8. H - O O O - O Intramolecular Aldol H H - H O O O O O H A beta hydroxy ketone

  9. What would happen? or

  10. What would happen? • Consider carefully • Remember, five and six membered rings are most stable or

  11. Recognizing Aldol Products • Product is a b-hydroxy aldehyde or ketone • Removing the bond between the Cα – Cβ reveals the carbon units that were joined in the aldol condensation

  12. Recognizing Aldol Products • The hydroxy becomes a carbonyl H O H O

  13. How would you make these Compounds by an Aldol Condensation reaction? • a b-hydroxy These are: and aldehyde a β-hydroxy ketone β β

  14. Identify the bond between the α- and b-carbon atoms • Delete the bond between the α- and b-carbon atoms • Change the C-OH into a C=O β α α β

  15. More

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