CH 12: Reactions of Aldehydes and Ketones

Compared to C=C in alkenes, C=O is ________,_________, and ____ ____.

stronger, shorter, and more polar

Rules for naming aldehydes

1) Number the longest parent chain that always assigns aldehyde carbon as #1

2) Name the parent chain. Replacing -e w/ -al.

2a) If the aldehyde is attached to a ring, then use the suffix -carbaldehyde

3) Name the substituents.

4) List substituents before the parent name in alphabetical order.

Rules for naming ketone

1) Number the longest parent chain that always assigns ketone carbon as the lowest #

2) Name the parent chain. Replacing -e w/ -one.

3) Name the substituents.

4) List substituents before the parent name in alphabetical order.

If ketone is a substituent, then it will be called “____.”

oxo

Compared to other functional groups, what kind (high or low) of BP do aldehydes and ketones have? Why?

To alkanes or ethers, aldehydes and ketones have a higher BP b/c they are MORE polar than them.

To alcoholes, aldehydes and ketones have a lower BP b/c they do not do H-bonding.

What reagents reacts w/ 2° alcohol to form a ketone?

Jones reagent (CrO₃ or Na₂Cr₂O₇, H₂SO₄, and H₂O) or PCC

What reagents reacts w/ 1° alcohol to form an aldehyde?

PCC

What reagents reacts w/ benzene to form a ketone on it?

acyl chloride and AlCl₃

What reagents reacts w/ terminal alkyne to form a ketone?

1) Hg(OAc)₂, H₂O

2) NaBH₄

What reagents reacts w/ terminal alkyne to form an aldehyde?

1) BH₃, THF

2) H₂O₂, NaOH

What reagents reacts w/ internal alkyne to form a ketone?

1) BH₃, THF

2) H₂O₂, NaOH

What reactions prepare aldehydes and ketones?

1) oxidation of alcohols

2) Fridel-Crafts Acylation

3) hydration of terminal alkyne

4) hydration of internal alkyne

What kind of reaction do aldehydes and ketones usually undergo? What do they serve as nucleophile/electrophile/acid?

nucleophilic addition reaction; electrophile

Which of the two (aldehyde or ketone) are more reactive? Why?

aldehydes b/c its carbonyl is more reactive and has less alkyl groups, so less stabilization from the inductive effect

1) What reagents reduces aldehydes and ketones to alcohols? What kind (soft or hard) of hydride is it? What is its purpose?

1) LiAlH₄ or LAH, THF

2) H₃O⁺

• hard hydride

  • reduces all carbonyl groups

2) What reagents reduces aldehydes and ketones to alcohols? What kind (soft or hard) of hydride is it? What is its purpose?

1)NaBH₄,

2) H₃O⁺

• soft hydride

  • reduces only aldehydes and ketones

What reagents reacts w/ aldehyde or ketone in acidic condition to form 1,1-diols?

H₂O, H⁺ (or H₃O⁺) or CH₃OH, H⁺

What reagents reacts w/ aldehyde or ketone in basic condition to form 1,1-diols?

NaOH, H₂O or M—OH (M = metals), H₂O

What reagents reacts w/ aldehyde or ketone to form hemiacetals?

1 eq. R—OH, H⁺

What reagents reacts w/ aldehyde or ketone to form acetals?

2 eq. R—OH, H⁺

What reagents reacts w/ aldehyde or ketone to form imines?

NH₃, H⁺ or R-NH₂, H⁺

What reagents reacts w/ aldehyde or ketone to form alkyl substituents?

Zn(Hg), HCl, and H₂O

What reagents reacts w/ aldehyde or ketone to form alkanes?

1) H₂N—NH₂ (hydrazine)

2) KOH or NaO, heat

Out of the 7 reactions of aldehydes and ketones, which one is pH dependent?

Formation of Imines

Out of the 7 reactions of aldehydes and ketones, which one requires a molecule to be stable in hot acid?

Clemmensen reduction

Out of the 7 reactions of aldehydes and ketones, which one requires a molecule to be stable in very strong base?

Wolff-Kishner reduction