Aldehydes and Ketones
Module Overview
This module covers aldehydes and ketones as the substrates and products of redox reactions. Structure is explained with both Lewis structures and molecular orbitals to discuss mechanisms in the context of green chemistry. Students need to be familiar with organic functional groups, reactions, and proposing a mechanism.
There are four units: 1.) nomenclature, structure, and oxidation state, 2.) reduction of aldehydes and ketones, 3.) carbon-carbon bond forming reactions of carbonyls, 4.) oxidation to make aldehydes and ketones, and retrosynthetic analysis. Unit 1 also serves as a platform to introduce and reinforce the concepts of systems thinking using a Systems Oriented Concept Map Extension (SOCME) assignment to consider the oxidation spectrum of retinoids for treating acne and wrinkles.
Green chemistry concepts include: 1.) using biofeedstocks for oxidation-state matching to improve multi-step synthesis, 2.) synthetic efficiency, 3.) preventing waste through reagent selectivity and balanced reactions, 4.) avoiding the toxicity and hazards of reagents and by-products, and 5.) chemical and enzymatic redox catalysis. UN SDGs 3: Good Health, 8: Safe Working Environment, 10: Reduced Inequalities, 12: Responsible Consumption and Production, and 13: Climate Action are addressed in this module.
Module Goal
The goal of this module is to understand the structure, reactions, and uses of aldehydes and ketones. Conventional redox reactions as a class comprise some of the most wasteful and toxic reactions, and greener redox reactions are an opportunity to update the curriculum with more sustainable chemistry. Students will use mechanism-based understanding of nucleophiles and electrophiles to choose greener reaction conditions for redox reactions of aldehydes and ketones as starting materials (including some as biofeedstocks), or products of alcohol oxidation. Students will evaluate and develop a Systems Oriented Concept Map Extension (SOCME) to compare and evaluate the environmental impact, toxicity, and life cycle from source to the end-fate of retinoids in skin treatments.
Audience
Second-semester organic chemistry undergraduates
Class Time Requirement
Approximately two 75-minute or three 50-minute consecutive class periods
Module Authors
Felicia A. Etzkorn, Virginia Tech; Jamie L. Ferguson, Emory & Henry College; Maggie B. Bump, Virginia Tech
Module Summary
Assumed Prior Knowledge
This module is designed to be used in the second semester of organic chemistry. It may come before carboxylic acid derivatives and reactions alpha to carbonyls. Students need to be familiar with organic functional groups, reactions, and drawing a mechanism.
Learning Objectives
Students will be able to:
- Understand the structure, properties, and reactivity of aldehydes and ketones.
- Recognize that reactants are available in a variety of oxidation states for the same carbon core structure.
- Choose a biofeedstock that is close to the oxidation state of the desired product for fewer steps.
- Determine whether a reduction or oxidation has occurred, based on the structure of organic reactants and products.
- Predict the reactant, reagent, product, and by-products of a carbonyl reaction.
- Recognize the parallels between chemical and biochemical reagents.
- Evaluate the sustainability of reducing and oxidizing reagents based on source, by-product waste, hazards, and suitability for the desired reaction.
- Propose the mechanism of a carbonyl reaction.
- Design a synthesis by retrosynthetic analysis that uses redox and carbon-carbon bond-forming reactions of carbonyl compounds.
Unit Overview
Unit 1: Structure, Properties, and Oxidation State
1.1 | Unit 1 Pre-class reading (90 minutes outside of class) |
1.2 | Lecture (30 minutes in class). In-class Activity: Carbonyls Reactivity Ranking. In-class Activity: Choose the Oxidation State Order |
1.3 | Homework: Oxidation State (60 minutes outside of class): Unit 1 homework plus #8 Retinoids Systems Thinking Map (SOCME) in groups of three (45 minutes) |
Unit 2: Reduction Reactions of Aldehydes and Ketones
2.1 | Unit 3 Pre-class reading (50 minutes outside of class) |
2.2 | Lecture (45 minutes in class). In-class Activity: Greener NaBH4 Reduction of Carbonyls. |
2.3 | Homework: Reduction of Aldehydes and Ketones (30 minutes outside of class) |
Unit 3: Carbon-Carbon Bond-Forming Reactions of Carbonyls
3.1 | Unit 3 Pre-class reading (30 minutes outside of class) |
3.2 | Lecture (25 minutes in class): Slides 31-41. In-class Activity: Organolithium and Organomagnesium. In-class Activity: Phosphorus Ylide Reactions. |
3.3 | Homework: Carbon-Carbon Bond-Forming Reactions (20 minutes outside of class) |
Unit 4: Oxidation and Retrosynthetic Analysis
4.1 | Unit 4 Pre-class reading (30 minutes outside of class) |
4.2 | Lecture (50 minutes in class). In-class Activity: Oxidation Reactions (matching). In-class Activity: Locate the Origins of Oxidized Monomers in Lignin. In-class Activity: Retrosynthetic Analysis (5 minutes in class) |
4.3 | Homework: Oxidations and Retrosynthetic Analysis (15 minutes outside of class) |
Download Module
Carbonyls Redox: Aldehydes and Ketones Includes:
- Module Overview Document
- Units 1-4
- Formative Assessments
- Summative Assessments
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About the Green Chemistry Module Project
The ACS Green Chemistry Instiute has partnered with chemistry instructors from over 45 institutions to develop green chemistry education resources for undergraduate students studying general and organic chemistry.
