Organic Chem Nomenclature

Question 1

For straight chain alkanes what is the process for naming?

Answer 1

1. Count the number of carbons
2. Use the appropriate prefix (meth, eth, prop, but, pent, hex, hept, oct, non, dec)
3. End all alkanes with the “ane-“ suffix

Question 2

What is the process for naming branched alkanes?

Answer 2

1. Find the longest chain of carbons within the structure and name it as you would a straight chain alkane. (this will be the foundation of the name, all branches are written in front of it)
2. Identify branches and choose the correct prefix (meth, eth, prop) and end the side chain with an “-yl” suffix
3. Make sure you number the parent chain in which each branch obtains the smallest number it can get.
4. Write all side chains in alphabetical order with names separated by hyphens and numbers separated by commas
5. If there are multiple of the same side chain, put both numbers in ascending order separated by commas and put a prefix in front of your side chain name (di, tri, tetra, penta - these are ignored when placing in alphabetical order)

Question 3

What is the process for naming alkenes?

Answer 3

1. Identify the longest carbon chain that includes ALL double bonds
2. When a double bond is present, the suffix for the parent chain is “-ene”
3. Double bonds take priority over side chains and therefore get the smallest number
4. When multiple double bonds are present, we use the di, tri, tetra, etc prefixes to show that (these prefixes are placed before the suffix rather than in front of the entire name - “-diene, -triene, -tetraene)

Question 4

How do we incorporate trans and cis into the nomenclature?

Answer 4

1. If the chains on either side of a double bond are on the same side -> you put “cis-“ in front of your entire name
2. If the chains on either side of a double bond are on opposite sides -> you put “trans-“ in front of your entire name

Question 5

What is the process in naming alkynes?

Answer 5

1. Triple bonds take priority unless a double bond is present in which the double bond takes priority however which ever bond is closest to the beginning of the chain gets too priority.
2. The parent chain must include all double and triple bonds