3 - Carbonyls and Amines Flashcards
Carbonyl=
***THINK TWO THINGS***
1)
2)
Carbonyl= is a carbon double bonded to an oxygen.
-the double bonds is shorter and stronger than the double bond of an alkene.
***THINK TWO THINGS***
1) Planar stereochemistry–> leaves open space above and below, allowing chemical attack
2) partial positive charge on the carbon–> means that any attack will be from a nucleophile
What typically undergoes nucleophilic addition? while what other goes under nucleophilic substitution.
What are more polar and have higher BPs than alkanes and alkenes of similar weight? However with no hydrogen bonding they have lower BPs than?
*Aldehydes and ketones typically undergo nucleophilic addition, while other carbonyl compounds prefer nucleophilic substitution.
*Aldehydes and ketones are more polar and have higher boiling points than alkanes and alkenes of similar weight. However with no hydrogen bonding they have lower boiling points than alcohols.
Substrate in nucleophilic addition=
Alpha-carbon=
*the ________ increases the acidity of the alpha hydrogen between the carbonyls, making it more acidic than _______.
Tautomerization=
Substrate in nucleophilic addition= most of the time aldehydes and ketones will be acting as this, or as a bronsted-lowry acid by donating one of its alpha-hydrogens.
Alpha-carbon= a carbon that is attached to a carbonyl carbon is in the alpha position.
*the dicarbonyl increases the acidity of the alpha hydrogen between the carbonyls, making it more acidic than water or alcohol.
Tautomerization= involves a proton shift.
Aldol condensation=
Wittig reaction=
*Aldehyde reduction results in a _________
Aldol condensation= an MCAT favorite because it demonstrates both alpha-hydrogen activity and the susceptibility of carbonyl carbons to a nucleophile.
-acid catalyzed
Wittig reaction= converts a ketone to an alkene.
-phosphorous ylide is used.
*Aldehyde reduction results in a primary alcohol.
Nucleophilic substitution reaction=
*carboxylic acids are able to form _______
Nucleophilic substitution reaction= look for carboxylic acid to behave as an acid or as the substrate in a nucleophilic substitution reaction.
*carboxylic acids are able to form hydrogen bonded dimers.
Decarboxylation=
*Acid chlorides are the most _______ carboxylic acid derivatives because of the ________. Acid chlorides love ________
Decarboxylation= when a carboxylic acid loses CO2.
-exothermic but hard to carry out with a high activation energy.
*Acid chlorides are the most reactive carboxylic acid derivatives because of the stability of the Cl- leaving group. Acid chlorides love nucleophiles.
Esters=
Transesterification=
Acetoacetic ester synthesis=
Amides=
Esters= alcohols react with carboxylic acids through nucleophilic substitution to form esters.
Transesterification= where one alkoxy group is substituted for another. When an alcohol reacts with an ester.
Acetoacetic ester synthesis= is the production of a ketone from acetoacetic ester due to the strongly acid properties of the alpha hydrogen.
Amides= are formed when an amine acting as a nucleophile substitutes at the carbonyl of a carboxylic acid or one of its derivatives.
*REACTIVENESS*
5 groups
Acyl chloride>>acid anhydride>>carboxylic acid>>ester>>amide
Amines=
*nitrogen can take ______ bonds.
Three important considerations:
1)
2)
3)
Amines= are derivatives of ammonia.
*nitrogen can take three or four bonds.
- *Three important considerations:**
1) may act as lewis base donating their lone pair of electrons
2) may act a nucleophile where the lone pair of electrons attacks a positive charge
3) nitrogen can take on a fourth bond (becoming positively charged)
Ammonia and amines act as ________
*ammonia, primary amines, and secondary amines ________, which raise boiling point and increases solubility.
Imines & Enamines=
Wolff-kishner reduction=
Ammonia and amines act as weak bases
*ammonia, primary amines, and secondary amines hydrogen bond, which raises boiling point and increases solubility.
Imines & Enamines= amines react with aldehydes and ketones losing water to produce these two.
Wolff-kishner reduction= reduce a ketone or aldehyde by removing the oxygen and replacing it with two hydrogens.
Hofmann elimination=
Hofmann degradation=
Phophoric acids when heated forms ____________. They also react with ________ to form esters.
Hofmann elimination= heating quarternary ammonium hydroxide to form an alkene.
Hofmann degradation= primary amides react with strongly basic solutions of chlorine or bromine to form primary amines with carbon dioxide as a by-product. “Hofmann rearrangement”
Phophoric acids when heated forms phosphoric anhydrides. They also react with alcohols to form esters.
