# 3: Functional Groups and Nomenclature

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learning objectives

After reading this chapter and completing ALL the exercises, a student can be able to

• use R groups to draw generic functional groups - refer to section 3.1
• name alkanes, cycloalkanes, alkenes, alkynes, alkyl halides, ethers, alcohols, amines, benzene and its derivatives, aldehydes, ketones, amines, carboxylic acids, and carboxylic acid derivatives using IUPAC (systematic) and selected common name nomenclature - refer to sections 3.2 - 3.14
• draw the structure of alkanes, cycloalkanes, alkenes, alkynes, alkyl halides, ethers, alcohols, amines, benzene and its derivatives, aldehydes, ketones, amines, carboxylic acids, and carboxylic acid derivatives from the IUPAC (systematic) and selected common names - refer to sections 3.2 - 3.14
• classify alkyl halides, alcohols and amines - refer to sections 3.5, 3.8, and 3.12 respectively.

A Pearl of Wisdom: Most common names were derived from older systems of nomenclature that some may argue were "not systematic at all". However, it is helpful to note that the older systems of nomenclature were often based on shared structural features and/or chemical reactivity. Learning carefully selected common names can offer insights into chemical reactivity and structural patterns. Additionally, there are some common names that are so prevalent, they need to be memorized.

Please note: The nomenclature for organic compounds with sulfur and phosphorus are introduced so that students can interpret a given name and draw the correct structure. Derivation of names can be required by the professor and requires additional instruction.

• 3.1: Generic (Abbreviated) Structures (aka R Groups)
It is not always necessary to draw the entire structure of a compound.  The correct use of the "R group" is explained.
• 3.2: Overview of the IUPAC Naming Strategy
The International Union of Pure and Applied Chemistry (IUPAC) names for organic compounds all follow the same set of rules and can have up to four parts.  Recognizing the overall pattern can simplify the learning process.
• 3.3: Alkanes
Alkanes form the carbon backbone of all organic compounds.
• 3.4: Cycloalkanes
The rotational limits of cycloalkanes introduce stereochemistry to some compounds.  Some disubstituted cycloalkanes can exist as geometric isomers (cis/trans).
• 3.5: Haloalkane - Classification and Nomenclature
The reactivity of the alkyl halides (haloalkanes) can be predicted using their structural classifications of primary, secondary, or tertiary.
• 3.6: Alkenes
The rigid, carbon-carbon double bond (C=C) can also introduce stereochemical considerations in naming.
• 3.7: Alkynes
The linear geometry of carbon-carbon triple bonds simplifies the names of this functional group.
• 3.8: 3.8 Alcohols - Classification and Nomenclature
Alcohols are organic compounds with hydroxyl groups as a unique structural feature.  Alcohol classification will be useful as we learn patterns of chemical reactivity.  The terms "vicinal" and "germinal" are also explained.
• 3.9: Ethers, Epoxides and Sulfides
Ethers, epoxides, and sulfides all have the heteroatom disrupting the continuous carbon chain.  There is no IUPAC suffix for ethers.  The alkoxy group is always a substituent.
• 3.10: Benzene and its Derivatives
This section focuses on naming benzene derivatives and the important distinction between a phenyl group and a benzyl group. Phenol nomenclature and with other important benzene derivatives are discussed.
• 3.11: Aldehydes and Ketones
While there are many functional groups that include the carbonyl structural feature, aldehydes and ketones are collectively referred to as "the carbonyls."  With their highly similar chemical reactivity, their nomenclature is taught together.
• 3.12: 3.12 Amines - Classification and Nomenclature
Amines are important weak bases, organic reactants. and biologically active compounds, such as alkaloids.  Amine classification is helpful in recognizing patterns of chemical reactivity.
• 3.13: Carboxylic Acids
Carboxylic acids are important natural products and synthetic precursors.  The common names are provided for carboxylic acids (1 to 10 carbons) and selected dicarboxylic acids.
• 3.14: The Carboxylic Acid Derivatives
All of these functional groups can be hydrolyzed to form carboxylic acids, so they are collective called the carboxylic acid derivatives.