Ch. 23

Question 1

Carbonyl Condenstion Reaction

Answer 1

Comprises two carbonyl partners and involves nucleophilic addition and alpha-substitution processes

1. Carbonyl converted by base into a nucleophilic enolate ion (nucleophilic donor) = alpha-substitution
2. Addtion of nucleophilic enolate ion to electrophilic carbonyl (electrophilic acceptor) = nucelophilic addition

Question 2

Adol Reaction

Answer 2

reversible reaction that involves two aldehydes/ketones

1. lead first to beta-hydroxy aldehyde/ketone
2. then dehydrated to alpha,beta-unsaturated products

Question 3

Claisen Condensation Reaction

Answer 3

Carbonyl condensation between two ester components that produces a beta-keto ester product; reversible, similar mechanism to aldol reaction

Question 4

Dieckmann Cyclization Reactions

Answer 4

Intermolecular claisen condensations that yield fix/six-membered cyclic beta-keto esters starting from 1,6 and 1,7-diesters; similar to clasien condensation; product can be futher alkylated

1,6-Diesters form 5-membered rings
1,7-Diesters form 6-membered rings

Question 5

Michael Reaction

Answer 5

Involves a conjugated additon of a carbon nucleophile (enolate) to an alpha,beta unsaturated acceptor/carbonyl compound

best rxns are between relatively acidic donors/stable enolates (beta-keto esters/beta-diketones) and unhindered alpha,beta-unsaturated acceptors/carbonyl compounds

Question 6

Robinson Annulation Reaction

Answer 6

Comprises a Michael addition and an intramolecular aldol cyclization forming a substituted cyclohexenone (substituted ring systems)

1. Michael additon by treatment of a beta-diketone/beta-ketone ester (nucleophilic donor) with an unsaturated ketone (acceptor);
   1,5-diketone intermediate
2. Intramolecular aldol cyclization/condensation

Question 7

What are the four common carbonyl group reactions?

Answer 7

Nucleophilic addition, nucleophilic acyl substituion, carbonyl alpha-substitution, and carbonyl condensation

Question 8

Mixed Adol Condensation

Answer 8

Two different aldehydes/ketones; give mixture of four possible products (two self-condensation and two mixed products)

Question 9

Intramolecular Aldol Condensations of 1,4 and 1,5-diketones

Answer 9

yield five/six-membered cyclic rings; more strain-free ring predominates

Question 10

Mixed Claisen Condensation

Answer 10

only successful when one of the two partners have no acidic alpha-hydrogens (ex. ethyl benzoate/ethyl formate); only function as acceptor partner

Question 11

What are good Michael donors?

Answer 11

Enamines; prepared by rxn of ketone with disubstituted amine (Stork Reaction)

Question 12

Aldol Reaction Reagents (Regular, Mixed and Intramolecular)

Answer 12

NaOH, ethanol

Question 13

Mixed Aldol Reaction Reactants

Answer 13

1. PhCHO

2. CH2O

Question 14

Dehydration of Aldol reagent

Answer 14

NaOH or H3O+

Question 15

Claisen Condensation reagent (Regular, Mixed, and Intramolecular)

Answer 15

Na+ -OEt, ethanol

Question 16

Mixed Claisen Condensation reactants

Answer 16

HC=OOEt

Question 17

Michael Reaction Reagent

Answer 17

Na+ -OEt, ethanol

Question 18

Carbonyl condensations with enamines reagents

Answer 18

1. THF solvent

2. H3O+

Question 19

What type of reaction is aldol condensation reaction?

Answer 19

base-catalyzed dimerization of two aldehydes/ketones

Question 20

Does the equilbrium of aldehydes/ketones in aldol reaction favor the products or reactants?

Answer 20

Products

Question 21

Dehydration of Aldol Products

Answer 21

yield alpha, beta-unsaturated aldehydes and ketones; catalyzed by both acid and base; slightly more severe than condensation

Question 22

Are conjugated enones or nonconjugated enones more stable?

Answer 22

Conjugated enones are more stable

Question 23

When can a mixed aldol reaction form a single product?

Answer 23

1. one carbonyl component has no alpha-hydrogens

2. one carbonly compound is more acidic than the other

Question 24

Mixed Claisen Condensation

Answer 24

1. Two different esters with one component having no alpha hydrogens
2. Ketone and ester with no alpha hydrogens

Question 25

What are Michael donors and acceptors?

Answer 25

Stable enolates = Michael donors

Alpha,beta-unsaturated compounds = Michael acceptors

Question 26

Stork Reaction

Answer 26

Ketone converted into an enamine to act as a Michael donor;
equivalent to Michael addition of ketone to yield a 1,5-diketone product

1. Enamine formation to form ketone
2. Michael-type addition to alpha,beta-unsaturated carbonyl compound
3. Enamine hydrolysis back to ketone