CHAPTER THREE

Alkanes and Cycloalkanes

Learning Objectives: Name both cyclic and acyclic compounds. Become familiar with organic nomenclature. Be able to do one of three things: name a given structure, draw a structure when given the name (most important), and recognize an incorrectly named structure. Recognize and name cis-trans isomers.

Identify functional groups and draw molecules containing them

3.1, 3.2, 3.18, 3.21, 3.22, 3.23, 3.24, 3.31

Draw all of the possible isomers of a given molecular formula

3.3, 3. 4, 3.5, 3.6, 3.19, 3.20, 3.23, 3.25, 3.26

There is no simple rule that allows you to determine how many isomers are possible. Be careful about drawing the same structure twice in a different representation (Look for symmetry).

Nomenclature

3.7, 3.11, 3.12, 3.13, 3.14, 3.28, 3.35, 3.36, 3.37

Identify 1^o, 2^o, and 3^o hydrogens, carbons and functional groups

3.8, 3.9, 3.10, 3.27, 3.34

Cycloalkanes: structure and nomenclature

3.15, 3.16, 3.17, 3.40, 3.41, 3.42

Helpful Hints for Chapter 3

1. Carbon and hydrogen atoms are designated as primary, secondary, tertiary, or quaternary, depending on how many substituents are attached.

2. IUPAC nomenclature rules must be learned, then many examples must be practiced so you know how to use the rules. Practice in groups. You can make it a party! Make sure you know the names of the simple alkyl groups: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl (p. 82).

3. Constitutional isomer have different atom connectivities and will have different names, e.g. 2-methylhexane and 3-methylhexane.

4. Stereoisomers have the same connectivity, but different placement of groups in space.

5. Disubstituted cycloalkanes can be either of two stereoisomers, cis (same side) or trans (opposite side). Make models of some examples and compare cis and trans isomers.