Oxidation of Aldehydes and Ketones

Oxidation of aldehydes and ketones.

The organic chemistry reactions that help a person understand biochemistry are the reactions you need to focus on for the new MCAT, not only because the reactions themselves show up on the exam but even more so because without organic chemistry knowledge, biochemistry reads like a story without a plot. Of themes from organic chemistry, the oxidation and reduction of organic compounds is one of the most important to have in your toolbox for understanding biochemical mechanisms.

WikiPremed Resources

Combustion
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Oxidation of Alkenes to Vicinal Diols
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Oxidative Cleavage of Alkenes
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Ozonolysis of Alkenes
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Oxidation of Alcohols
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Reduction of Ketones and Aldehydes
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Reduction of Aryl Alkyl Ketones
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Oxidation of Aldehydes and Ketones
Mechanisms and explanations from the Organic Mechanisms Pocketbook

The Wolff-Kishner Reaction
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Nitrile Reduction
Mechanisms and explanations from the Organic Mechanisms Pocketbook

Oxidation-Reduction in Organic Chemistry Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Oxidation-Reduction in Organic Chemistry
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Learning Goals

Proficiency 

Be ready to assign the oxidation number of carbon with fluent ease within the various organic functional groups.

Understand the sequence of alkanes, alcohols, aldehydes & ketones, and carboxylic acids as a series of oxidation states.

Recall the oxidizing and reducing agents employed in the organic chemistry laboratory and how they are used.

Be aware of special case redox reactions such as benzylic oxidation and other cases where oxidation may result in cleavage or decarboxylization.

Be able to describe the change in oxidation state undergone by sulfur in transitioning from a thiol to a disulfide.

Suggested Assignments

Get oriented to oxidation-reduction in electrochemistry using the question server. Complete the fundamental terms crossword puzzle. Here is the solution to the puzzle.

Review the web resources for oxidation-reduction in organic chemistry.

Conceptual Vocabulary for Oxidation-Reduction in Organic Chemistry

Combustion
Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames.
Permanganate
Potassium permanganate contains manganese bonded to four oxygens. Often employed for laboratory redox, it is a strong oxidizer with manganese in the +7 oxidation state.
Lithium aluminium hydride
Lithium aluminium hydride is a powerful reducing agent used in organic chemistry.
Sodium borohydride
Prepared by the reaction of sodium hydride on trimethylborate, sodium borohydride is a reducing agent often used to reduce aldehydes and ketones into alcohols.
Hydride
Hydride is the name given to the negative ion of hydrogen. Although this ion does not exist except in extraordinary conditions, the term is widely applied to describe compounds of hydrogen with other elements.
Chromate
An important group of oxidizing agents, the chromates are salts of chromic acid.
Hydroboration-oxidation reaction
Employing borane in tetrahydrofuran in the first step, the hydroboration-oxidation reaction is a two-step organic chemical reaction that converts an alkene into a neutral alcohol by the net addition of water across the double bond.
Hydrogenation
Hydrogenation is a class of chemical reactions which result in an addition of hydrogen molecule usually to unsaturated organic compounds.
Oxidative addition
Oxidative addition is an important classes of reactions in organometallic chemistry in which a metal complex with vacant coordination sites and a relatively low oxidation state is oxidized by the insertion into a covalent bond.
Reductive elimination
The reverse of oxidative addition is reductive elimination.
Tollens reagent
Tollens' reagent is usually ammoniacal silver nitrate, an oxidizing agent, which is itself reduced to silver metal. It is used as a test for aldehydes.
Manganese
Manganese(IV) oxide is the chemical compound in which manganese is bound to two oxygens. It is often used to oxidize allylic alcohols to the corresponding aldehydes.
Lindlar catalyst
Used for the hydrogenation of alkynes to alkenes, Lindlar catalyst is a heterogeneous catalyst that consists of palladium deposited on calcium carbonate and treated with various forms of lead.
Ozonolysis
Ozonolysis is the cleavage of an alkene or alkyne with ozone to form compounds in which the multiple carbon-carbon bond has been replaced by a double bond to oxygen.
Hydrogenolysis
Hydrogenolysis is a catalytic chemical reaction whereby a molecule of hydrogen is added over a carbon-heteroatom single bond, effectively causing a lysis of the bond.
Wolff-Kishner reduction
The Wolff-Kishner reduction is a chemical reaction that fully reduces a ketone (or aldehyde) to an alkane.
Jones oxidation
The Jones oxidation is a chemical reaction described as the chromic acid oxidation of primary and secondary alcohols to carboxylic acids and ketones, respectively.
Clemmensen reduction
The Clemmensen reduction is a chemical reaction described as a reduction of ketones or aldehydes to alkanes using zinc amalgam and hydrochloric acid.
One-electron reduction
A one-electron reduction in organic chemistry involves the transfer of an electron from a metal to an organic substrate.
Pyridinium chlorochromate
Pyridinium chlorochromate is a reddish orange solid reagent used to oxidize primary alcohols to aldehydes and secondary alcohols to ketones.
Collins Reagent
Collins reagent is the complex of chromium(VI) oxide with pyridine in dichloromethane. It is used to selectively oxidize primary alcohols to the aldehyde, and will tolerate many other functional groups within the molecule.
Peroxy acid
A peroxy acid is an acid in which an acidic -OH group has been replaced by an -OOH group.
Raney nickel
Raney nickel is a solid catalyst composed of fine grains of a nickel-aluminium alloy, used in many industrial processes, most commonly for hydrogenation reactions.
Advanced terms that may appear in context in MCAT passages
Rosenmund reduction
The Rosenmund reduction is a chemical reaction that reduces an acid halide to an aldehyde using hydrogen gas over palladium-on-carbon poisoned with barium sulfate.
Cannizzaro reaction
The Cannizzaro reaction is a chemical reaction that involves the base-induced disproportionation of an aldehyde lacking a hydrogen atom in the alpha position.
Fremy's salt
Fremy's salt is a chemical compound and a strong oxidizing agent. The formal name is disodium nitrosodisulfonic acid the name refers equally well to the potassium salt potassium nitrosodisulfonate.
Swern oxidation
The mild Swern oxidation is a chemical reaction whereby a primary or secondary alcohol is oxidized to an aldehyde or ketone using oxalyl chloride, dimethyl sulfoxide and an organic base, such as triethylamine.
Corey-Kim oxidation
The Corey-Kim oxidation is an oxidation reaction used to synthesise aldehydes and ketones from primary and secondary alcohol
Meerwein-Ponndorf-Verley reduction
The Meerwein-Ponndorf-Verley-Reduction in organic chemistry is the reduction of ketones to secondary alcohols with aluminumisopropylate catalysis in isopropanol solution.
Oppenauer oxidation
Oppenauer oxidation is a gentle method for oxidizing secondary alcohols to ketones. The reaction is the opposite of Meerwein-Ponndorf-Verley reduction.
Kornblum oxidation
The Kornblum oxidation is a chemical reaction of a primary halide with dimethyl sulfoxide (DMSO) to form an aldehyde.
IBX acid
IBX acid or 2-Iodoxybenzoic acid is an organic compound used in organic chemistry as an oxidizing agent, especially to oxidize alcohols to aldehydes.
Dess-Martin periodinane
Dess-Martin periodinane is an chemical reagent with multiple advantages used to oxidize primary alcohols to aldehydes and secondary alcohols to ketones.
Birch reduction
The Birch reduction is the organic reduction of aromatic rings with sodium in liquid ammonia to form 1,4-cyclohexadienes.
McMurry reaction
The McMurry reaction is an organic reaction in which two ketone or aldehyde groups are coupled to an alkene in the presence of a titanium chloride compound such as titanium(III) chloride and a reducing agent.