Alkenes and
Alkynes
SWBAT: Name and Draw
Alkenes and Alkynes
More Substituent Groups
 methoxy
 nitro
 neopentyl
-OCH3
-NO2
 neohexyl
 vinyl
 allyl
-CH=CH2
-CH2-CH=CH2
Only iso-, neo- are
alphabetized, tert, sec are not
neopentyl, neohexyl, vinyl and allyl are
usually only found on aromatic compounds
Alkenes – naming rules
 Number
longest continuous chain of
carbons, double bond receives lowest
possible numbers
 Alphabetize groups without using prefixes
 Use cis and trans stereoisomerism
 List the numbers for the double bonds
 Alkenes end in -ene
 If more than one double bond end in
diene, triene, tetraene
Alkenes Practice
5-chloro-2-hexene
1,5-dichloro-1,4-hexadiene
CH3–CH=CH–CH2–CH3
2-pentene
Alkenes Practice
trans-8-ethyl-3-undecene
5-bromo-4-chloro-7,7dimethyl-4-undecene
1,2-difluoro-cyclohexene
4-ethenylcyclohexanol
Tip – 11 carbon is undec-
Stereoisomerism
Carbon that is double bonded (alkenes) have an sp2
hybridization – so they are trigonal planer – ergo, we
need to account for placement of substituents
Cis
Trans
Alkenes Practice
c
5-chloro-cis-2-hexene
Cycloalkenes – naming rules
 Number
the carbons double bond
receives the lowest possible number, start
with #1
 Groups receive next lowest number
 List groups
 List double bond numbers
 Long chain name
 End in diene, triene, tetraene for multiple
double bonds
Naming alkenes (Don’t forget
the cis or trans)
5 – methyl – trans – 2 – heptene
Why is the cyclohexene numbered the way it is
numbered?
Alkynes
 Naming
is similar to alkenes except no cis
or trans.
 Alkynes end in -yne
Moodle
 Sign
out a computer
 Go to Moodle (link off my website)
 Go through all links under


Alkanes
Alkenes & Alkynes