Aldehydes and Ketones – Chapter 19 Vocabulary Review

Set of vocabulary flashcards summarizing key terms, reactions, and spectroscopic features of aldehydes and ketones covered in Chapter 19.

Aldehyde

Carbonyl compound bearing at least one hydrogen; named with the suffix “-al.”

Ketone

Carbonyl compound bearing two carbon substituents; named with the suffix “-one.”

Carbonyl Group

The C=O functional group common to aldehydes and ketones; strongly electrophilic.

Locant

Number assigned to indicate position of a functional group; carbonyl receives the lowest possible number.

Oxidation of Primary Alcohols

Laboratory method for preparing aldehydes.

Oxidation of Secondary Alcohols

Common laboratory method for preparing ketones.

Ozonolysis of Alkenes

Cleavage of alkenes with ozone that yields aldehydes and/or ketones.

Hydroboration-Oxidation of Terminal Alkynes

Two-step reaction that converts a terminal alkyne to an aldehyde.

Acid-Catalyzed Hydration of Terminal Alkynes

Adds water across a triple bond to give a ketone via tautomerization.

Friedel–Crafts Acylation

Electrophilic aromatic substitution that installs an acyl group, producing an aryl ketone.

Resonance Effect (Carbonyl)

Electron withdrawal through π-bond delocalization that increases carbonyl electrophilicity.

Inductive Effect (Carbonyl)

σ-Electron withdrawal by the carbonyl oxygen that polarizes the C=O bond.

Steric Effects in Reactivity

Crowding around a carbonyl; aldehydes are less hindered and therefore more reactive than ketones.

Nucleophilic Addition (Basic Conditions)

Two-step mechanism: (1) nucleophilic attack on carbonyl, (2) proton transfer.

Hydrate

Geminal diol formed when water adds to a carbonyl; equilibrium usually favors the carbonyl.

Hemiacetal

Intermediate bearing one –OR and one –OH on the same carbon; first product of acetal formation.

Acetal

Compound with two –OR groups on the same carbon produced from a carbonyl plus two alcohols under acid.

Cyclic Acetal

Five- or six-membered ring acetal formed from reaction of a carbonyl with a diol.

Protecting Group (Acetal)

An acetal used to mask a carbonyl because it is stable to strong base and nucleophiles.

Imine

Compound with C=N–R formed when an aldehyde or ketone reacts with a primary amine under acid.

Carbinolamine

Intermediate containing both OH and NH groups on the same carbon in imine formation.

Hydrazone

C=N–NH2 derivative formed when hydrazine reacts with a carbonyl compound.

Oxime

C=N–OH derivative formed when hydroxylamine reacts with a carbonyl compound.

Enamine

Alkene-amine (C=C–NR2) formed when a carbonyl reacts with a secondary amine under acid.

Wolff–Kishner Reduction

Basic treatment of a hydrazone that removes the C=O, giving an alkane.

Thioacetal

Product of a carbonyl and two equivalents of a thiol (or a dithiol) under acid.

Raney Nickel

Catalyst that desulfurizes thioacetals to give a methylene (CH2) group.

Lithium Aluminum Hydride (LiAlH4)

Powerful hydride donor that reduces aldehydes and ketones to alcohols irreversibly.

Sodium Borohydride (NaBH4)

Milder hydride donor that reduces aldehydes and ketones to alcohols.

Grignard Reagent (RMgX)

Organomagnesium nucleophile that adds to carbonyls forming alcohols with new C–C bonds.

Cyanohydrin

Compound with OH and CN groups on the same carbon formed by addition of HCN to a carbonyl.

Wittig Reaction

Conversion of a ketone or aldehyde to an alkene using a phosphorus ylide.

Phosphorus Ylide

R3P=CR2 species that acts as the nucleophile in a Wittig reaction.

SN2 Reaction

Bimolecular nucleophilic substitution used to prepare Wittig reagents from alkyl halides.

(Z)-Alkene (Wittig)

Major product when an unstabilized ylide reacts in a Wittig reaction.

(E)-Alkene (Wittig)

Major product when a stabilized ylide reacts in a Wittig reaction.

Baeyer–Villiger Oxidation

Peroxy-acid oxidation that inserts an oxygen next to a carbonyl, converting a ketone to an ester.

Lactone

Cyclic ester produced when a cyclic ketone undergoes Baeyer–Villiger oxidation.

Migratory Aptitude

Relative ability of substituents to migrate during Baeyer–Villiger oxidation, dictating regioselectivity.

Carbonyl IR Stretch

Strong absorption near 1715 cm⁻¹; conjugation lowers and ring strain raises the frequency.

Aldehydic C–H IR Bands

Two characteristic absorptions around 2700 and 2850 cm⁻¹.

¹H NMR Carbonyl Deshielding

Carbonyl group shifts neighboring protons about +1 ppm; aldehydic proton appears near 10 ppm.

¹³C NMR Carbonyl Signal

Weak resonance observed close to 200 ppm in the carbon spectrum.