Organic Chemistry Aldehydes, Ketones, and Carbohydrates: Key Names and Reactions

What is the common name for the simplest aldehyde, methanal (CH2O)?

Formaldehyde.

What is the common name for ethanal (CH3CHO)?

Acetaldehyde.

What is the common name for propanal (CH3CH2CHO)?

Propionaldehyde.

What is the common name for propan-2-one (CH3COCH3)?

Acetone.

What is the common name for diphenylmethanone?

Benzophenone.

What is the common name for 1-phenylethan-1-one?

Acetophenone.

What is the IUPAC name for phenylacetaldehyde?

2-phenylethanal.

What is the IUPAC name for the compound with a cycloheptane ring attached to a $-CHO$ group?

Cycloheptanecarbaldehyde.

What is the IUPAC name for 1,1,1-trichloroacetone?

1,1,1-trichloropropan-2-one.

What is the IUPAC name for a hexanal molecule with a hydroxyl group on carbon 4?

4-hydroxyhexanal.

A seven-carbon aldehyde with a triple bond starting at carbon 2 and a ketone group at carbon 5 is named _____.

5-oxo-2-heptynal.

What reagent is used to oxidize a primary alcohol to an aldehyde without further oxidation to a carboxylic acid?

Pyridinium chlorochromate (PCC) or a Swern oxidation.

What are the two key steps in the ozonolysis of an alkene to yield aldehydes or ketones?

1. Reaction with ozone (O3), followed by 2. a reductive workup with dimethyl sulfide ((CH3)2S).

The hydration of a terminal alkyne using aqueous sulfuric acid H2SO4 and mercury(II) sulfate (HgSO4) yields what type of functional group?

A methyl ketone.

The reaction of but-1-yne with H2O, H2SO4, and HgSO4 initially forms an unstable enol intermediate which then tautomerizes to what final product?

Butan-2-one.

What is the product of reacting propanal with sodium borohydride (NaBH4) in ethanol?

Propan-1-ol.

What is the product of reacting propanal with 1. lithium aluminum hydride (LiAlH4) followed by 2. an acidic workup (H3O+)?

Propan-1-ol.

What is the product when propanal reacts with phenylmagnesium bromide (C6H5MgBr) followed by an acidic workup (H3O+)?

1-phenylpropan-1-ol.

The reaction of an aldehyde with a phosphorus ylide, such as methylenetriphenylphosphorane (Ph3P=CH2), is known as the _____ reaction.

Wittig reaction.

What is the product of the Wittig reaction between propanal and Ph3P=CH2?

But-1-ene.

What is the name of the functional group formed when an aldehyde reacts with excess alcohol in the presence of an acid catalyst?

An acetal.

What is the product of reacting propanal with excess methanol (CH3OH$) and a catalytic amount of acid (H+)?

1,1-dimethoxypropane.

Reacting an aldehyde with a diol like ethylene glycol (HOCH2CH2OH$) and an acid catalyst forms what type of compound?

A cyclic acetal.

What is the product when propanal reacts with hydrazine (NH2NH2) under mildly acidic conditions (pH 4-5)?

Propanal hydrazone.

What is the product of reacting propanal with hydroxylamine (HONH2) at pH 4-5?

Propanal oxime.

Ketones typically do not react with mild oxidizing agents like Tollens' reagent, but aldehydes are oxidized. What is the product of oxidizing an aldehyde with Tollens' reagent (Ag(NH3)2)?

A carboxylate anion, which is protonated to a carboxylic acid upon acidic workup.

What is the product of reacting formaldehyde with phenylhydrazine (H2NNHPh) at pH 4-5?

Formaldehyde phenylhydrazone.

In carbohydrate chemistry, how can one determine if a Fischer projection represents a D-sugar or an L-sugar?

It is a D-sugar if the hydroxyl group on the bottom stereocenter (the one furthest from the carbonyl) points to the right.

Which form of sugar, D or L, is more common in nature?

D-sugars are far more common in nature.

What is the term for diastereomers that differ in configuration at only one stereogenic center?

Epimers.

Mannose is the C-2 epimer of glucose. How would its Fischer projection differ from that of D-glucose?

The hydroxyl group at carbon 2 would be on the left instead of the right.

Galactose is the C-4 epimer of glucose. How would its Fischer projection differ from that of D-glucose?

The hydroxyl group at carbon 4 would be on the left instead of the right.

What is the name for the cyclic form of glucose where the anomeric hydroxyl group is on the opposite side of the ring from the CH2OH group?

$\alpha$-glucose.

What is the name for the cyclic form of glucose where the anomeric hydroxyl group is on the same side of the ring as the CH2OH group?

beta-glucose.

A sugar that gives a positive Tollens' test is classified as a _____ sugar.

Reducing sugar.

Why is glucose considered a reducing sugar?

Because its cyclic hemiacetal form is in equilibrium with the open-chain aldehyde form, which can be oxidized by the Tollens' reagent.

Sucrose is a non-reducing sugar because both anomeric carbons are involved in the glycosidic bond, forming _____ linkages with no hemiacetal present.

Acetal.

What reagents can be used to convert a carboxylic acid into an acid chloride?

Thionyl chloride (SOCl2) or oxalyl chloride (COCl2).

What is the IUPAC name for the amide derived from hexanoic acid and N,N-dimethylamine?

N,N-dimethylhexanamide.

The inductive effect of electronegative atoms like fluorine _____ the acidity of a carboxylic acid by stabilizing the conjugate base.

Increases.

Why does benzoic acid react with sodium bicarbonate to produce bubbles, while phenol does not?

Benzoic acid is a strong enough acid to protonate bicarbonate, forming carbonic acid which decomposes to CO2 gas; phenol is not acidic enough.

What is the general product of the reaction between an acid chloride and an alcohol?

An ester.

What are the reagents for a Fischer esterification reaction?

A carboxylic acid and an alcohol with a catalytic amount of strong acid (e.g., H2SO4).

What is the product of heating a beta-keto acid?

A ketone and carbon dioxide (CO2) via decarboxylation.

The hydrolysis of an ester in the presence of a base like NaOH is called _____.

Saponification.

What is the product of reacting an acid chloride with a Gilman reagent, such as lithium dimethylcuprate (CH3)2CuLi)?

A ketone.

What is the product of reacting an ester with excess Grignard reagent followed by an acidic workup?

A tertiary alcohol, where two of the alkyl groups come from the Grignard reagent.

What reagent is used to reduce an ester to a primary alcohol?

Lithium aluminum hydride (LiAlH4).

What is the product of the complete hydrolysis of an amide under acidic conditions?

A carboxylic acid and an ammonium salt.

What is the product of hydrolyzing a nitrile (R-C=N) under acidic or basic conditions?

A carboxylic acid ($R-COOH$).

What is the common name for the dicarboxylic acid with two carbon atoms, HOOC-COOH?

Oxalic acid.

What is the common name for the dicarboxylic acid with four carbon atoms, HOOC-(CH2)2-COOH?

Succinic acid.

The tautomer of a ketone or aldehyde that contains a carbon-carbon double bond and a hydroxyl group is called an _____.

Enol.

Can benzaldehyde form an enol tautomer? Why or why not?

No, because it does not have any alpha-protons.

The deprotonation of a carbonyl compound at the alpha-carbon by a strong base forms a resonance-stabilized anion called an _____.

Enolate.

What is a suitable strong base for quantitatively deprotonating a ketone to form an enolate?

Lithium diisopropylamide (LDA).

Which proton is most acidic in ethyl acetoacetate?

The proton on the carbon between the two carbonyl groups.

What is the product of treating acetone with excess aqueous base (NaOH) and iodine (I2)?

Iodoform (CHI3) and acetate, via the haloform reaction.

What is the product of reacting cyclohexanone with 1) LDA at -78°C, followed by 2) methyl iodide (CH3I)?

2-methylcyclohexanone.

The reaction of a carboxylic acid with bromine (Br2) and phosphorus (P) or phosphorus tribromide (PBr3) followed by hydrolysis results in what product?

An alpha-bromocarboxylic acid (Hell-Volhard-Zelinsky reaction).

Can a gamma-keto acid undergo thermal decarboxylation?

No, only beta-keto acids and malonic acids readily undergo thermal decarboxylation.

What is the final product after treating diethyl malonate with 1) NaOEt, 2) an alkyl halide, 3) NaOH/H2O, and 4) H3O+ with heat?

A carboxylic acid, with the alkyl group from the alkyl halide attached to the alpha-carbon.

The reaction of an aldehyde or ketone with an enolate to form a $\beta$-hydroxy carbonyl compound is known as the _____ reaction.

Aldol addition.

The reaction of two molecules of an ester in the presence of an alkoxide base to form a $\beta$-keto ester is known as the _____ condensation.

Claisen condensation.

What is the general purpose of using a protecting group, such as forming a cyclic acetal from a ketone?

To temporarily block the reactivity of a functional group while another part of the molecule is being modified.

What reagents are needed to convert 1-bromopentane into hexanoic acid via a Grignard reaction?

1) Magnesium (Mg) in ether, 2) Carbon dioxide (CO2), followed by 3) an acidic workup (H3O+).

What reagents can be used to convert 1-bromopentane into hexanoic acid via a nitrile intermediate?

1) Sodium cyanide (NaCN), 2) hydrolysis with aqueous base (NaOH), followed by 3) an acidic workup (H3O+) with heat.

What is the product of the reaction between an acid anhydride and an amine?

An amide and a carboxylate salt

In the mechanism of acid-catalyzed acetal formation, what is the role of the acid catalyst?

To protonate the carbonyl oxygen, making the carbonyl carbon more electrophilic

What is the intermediate in the base-catalyzed hydrolysis (saponification) of an ester?

A tetrahedral alkoxide intermediate

What is the final product when phosgene (ClCOCl) reacts with excess methylmagnesium bromide?

2-methylpropan-2-ol (tert-butyl alcohol)

The reaction of phosgene with water in the lungs produces corrosive hydrochloric acid (HCl) and what other gas?

Carbon dioxide (CO2)