Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

CH 17: Aldehydes and Ketones → NAMING ALDEHYDES 

● Alkanal ○ Aldehyde function is always carbon #1 !  

● In cyclic form: cycloalkanecarbaldehyde 

 → NAMING KETONES 

● Alkanone ● In cyclic form: cycloalkanone ● Priority: aldehydes > ketones > alcohols 

○ As a substituent: oxo- 

 → SYNTHESIS OF ALDEHYDES AND KETONES  Recall previous reactions… 

 New reactions: 

● Oxidation of allylic alcohol: only the allylic alcohol gets oxidized. 

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

 → NUCLEOPHILIC ADDITION REACTIONS 

● C=O bond is polar and susceptible to reaction. ○ Acid acts as a catalyst by protonating the carbonyl O 

 ● Aldehydes are more reactive than ketones. 

○ Less steric hindrance ○ More electron deficient carbon (only one alkyl group attached--recall alkyl groups are 

electron donating)  → ADDITION OF WATER/ALCOHOL 

 ● Hemiacetals and geminal diols CANNOT be isolated; Carbon is too electron deficient 

○ You will get a mixture of your original carbonyl + the geminal diol/acetal ○ Equilibrium usually lies to the left with certain exceptions: 

 

 

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

 ● Unlike hemiacetals and geminal diols, acetals can be isolated! 

 ** Fill in mechanism below (all steps should be reversible)                 

● Intramolecular acetal formation is possible.  

 ● Recall 5 and 6 membered rings are the most stable. ● If you have two carbonyls on one molecule, acetals are a good way to protect one of those groups 

from reacting with your reagents.  

 ● Thioacetals can be formed similarly. 

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

○ can also do reactions that acetals cannot, like reduction with hydrogen. 

 → REACTIONS WITH AMINES 

● Ideal pH for these reactions is 4.5 - 5.5 (need acidic medium as a catalyst). Reactions are reversible. 

● Primary amine: forms an imine 

 ** Fill in mechanism below                

● Secondary amine: forms an enamine 

 ** Fill in the mechanism below:          

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

  

● Tertiary amine: NR → WOLFF KISHNER REDUCTION 

● Past methods of deoxygenation included H2, Raney Ni and Clemmensens reduction ○ Both are in acidic medium 

● Wolff Kishner red. Occurs in basic medium 

 ** Fill in the mechanism below:                   → HCN ADDITION 

● HCN can be synthesized using NaCN and an acid (HCl, H2SO4, etc..) 

 ** Fill in the mechanism (for both addition and removal of CN)         

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

 → YLIDE ADDITION 

 ** Fill in mechanism below, including ylide synthesis:            → OXIDATION TESTS FOR ALDEHYDES 

● Tollen’s reagent = [Ag(NH3)2]OH ○ Forms a silver mirror precipitate ○ Reacts only with aldehydes, not ketones 

● Fehling’s test = Cu2+, -OH, H2O  ○ Forms a brick red solid precipitate ○ Reacts only with aldehydes, not ketones 

 → BAEYER WILLIGER OXIDATION 

● Basically inserting an oxygen next to your carbonyl ● Migratory aptitude: H > tertiary > secondary > phenyl > primary > methyl 

○ Better migratory aptitude means the oxygen is more likely to stick itself in that position 

 ** Fill in the mechanism below:           

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

* PRACTICE 

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Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

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Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

CH 18: Enols/Enolates → ALPHA HYDROGENS 

 ● The alpha hydrogen is very acidic. This is due to resonance stability and inductive effects. 

○ The alpha H in aldehydes is more acidic than ketones (more electron deficient) ● Removal forms a special ion called an enolate ion: 

 ● An optically active aldehyde or ketone will lose it's optical activity in the presence of acid or base, 

proving that the alpha H is acidic: 

 ** Fill in the mechanism for an acidic medium:             ** Fill in the mechanism for a basic medium:           

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

→ ALPHA HALOGENATION ● In acidic medium -> monohalogenation 

 ** Fill in the mechanism below:            

● In basic medium -> polyhalogenation ○ All alpha H’s get replaced by the halogen 

● Iodoform test: ○ Used to test for presence of methyl ketones. Positive test yields a yellow precipitate. ○ Can use other halogens besides iodine too (except F) 

 ** Fill in the mechanism below:               → ALPHA ALKYLATION 

● The enolate ion can be used to do an alkylation reaction. ○ Problems:  

■ Must be a methyl halide or a primary haloalkane; otherwise E2 reaction may occur 

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

■ With aldehydes, there is a competing reaction: aldol condensation ■ With ketones, polyalkylation is possible. The first alkylation product may form 

another enolate and do another alkylation reaction 

 ● To avoid these problems, enamines can be used as a type of protecting group, since they have 

enolate ion characteristic. ○ Halide can be methyl, primary, or secondary ○ No polyalkylation 

 → ALDOL CONDENSATION 

  

● Yield is lower for ketones than aldehydes ● Requires at least two alpha hydrogens ● ALWAYS count your carbons to check your answer. (i.e. adding an ald with 3 C + ald with 4 C -> 

product should have 7 C) ** Fill in the mechanism below:               

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

● Intramolecular aldol condensation is possible. Recall, 5 and 6 membered rings are the most favorable. 

 ● When a reaction has two different aldehydes, mixed condensation occurs. 

 ● To prevent this from happening, make sure one of the reagents does not have 2 alpha Hs. ● Using a ketone can also be effective because ketones are less reactive than aldehydes. 

 → CONJUGATED ALPHA-BETA UNSATURATED ALDEHYDES AND KETONES 

● Aldol condensation leads to an important product: conjugated α-β-unsaturated aldehydes/ketones 

 ● Can be synthesized in other ways too: 

 ● Nucleophilic addition goes through two routes: 1,2 and 1,4 addition 

1,2 ADDITION: ● Involves only one double bond and not both ● Favored by RMgX, RLi, NaBH4, LiAlH4, X2 

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

 1,4 ADDITION 

● Involves both double bonds ● Favored by water, alcohols, enolates, enamines, amines, HCN, organocuprates (R2CuLi) 

 ** Fill in the mechanism below:         Organocuprates: 

      

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

Michael addition (addition of enolate ion): 

 ● There should be three carbons between the two carbonyls ● Again, count your carbons to make sure they are all accounted for. 

** Fill in mechanism:              → MICHAEL ADDITION 

● Michael addition followed by an intramolecular aldol condensation 

 ** Fill in the mechanism:                

Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

* PRACTICE: 

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Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

* KEY Refer to lecture notes for mechanisms. If you need help or have found any mistakes, e-mail me or come to my office hours (MON: 9 - 10:45 AM CHEM159 // TUES: 4:30 - 6:00 PM CHEM163K) 

CH 17 1. 4-hydroxy-2-pentanone 2. 4-oxo-2-cyclohexene-1-carbaldehyde 

3.  4. H2O, H2SO4, HgSO4 or hydroboration-oxidation 5. 1) O3 2) S(CH3)2 3) HS(CH2)3SH, H+, ZnCl2, heat 4) H2, Raney-Ni 

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9.  10. 1) PCC or Jones 2) NH2NH2, H2O, OH-, heat 

 CH 18 

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Nasiri CHE118B Final Study Guide Spring 2019 || S. Ly sdly@ucdavis.edu 

2.  3. 1) PCC or Jones 2) Br2, CH3COOH 3) NaHCO3 4) (CH3)2CuLi 5) CH3CH2Br 6) H2NCH3, H+ 

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