IUPAC Nomenclature Organic Compounds (Part 2) of

I. Naming Alkenes and Alkynes ( Unsaturated Compounds) Alkanes contain single bonds only -ANE ending C n H 2n+2 (saturated) Alkenes contain a double bond -ENE ending C n H 2n (unsaturated) Alkynes contain a triple bond between -YNE ending C n H 2n-2 (unsaturated)

Naming Alkenes & Alkynes Parent Name = longest continuous chain of carbon atoms Use Greek prefixes to indicate the presence of multiple identical branching groups. Name & position of branching groups (if any) + Change the ending of the parent name to - ene or -yne Indicate where double or triple bond is located +

What is the parent name?Butene (double bond present) What position is the double bond located ? Must number parent chain so the carbon atoms containing the double bond have the lowest number. Use the lowest number to indicate where the double bond starts. 1 position Correct name is : 1-butene Note: Carbon atoms can only have four bonds CCCC

What is the parent name?hexene (double bond present) What position is the double bond located ? 3 position Location and number of groups: Note: Always number so the double bond gets the lowest number CH 3 CH CH Correct name is : 2,5-dimethyl-3-hexene 2,5-dimethyl

(CH 3 ) 2 C=CHCH 2 C(CH 3 ) 3

2,5,5 – trimethyl-2-hexene

(CH 3 CH 2 CH 2 ) 2 C=CH 2

2-propyl-1-pentene

Hydrocarbons can also contain other atoms, such as halogens (F, Cl, Br, I). Halogen atoms are treated like branching alkyl groups. Halogen Group Name F fluoro C chloro Br bromo I iodo

Longest chain containing triple bond? Location and number of groups? Name: 6-chloro-5-ethyl-4-methyl-2-heptyne 5-ethyl heptyne (triple bond) 4-methyl6-chloro

6-chloro-3,3-dimethyl-4-octyne 4-bromo-5-methyl-2-hexyne