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12 Cards in this Set

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  • Back
Unsaturation Number
U = C + 1 - ½ (H) + ½ (N)

U = unsaturation number
H = number of hydrogens + halogens
N = number of nitrogens + phosphorus
Interpretation of Unsaturation Number-----0
no rings, no double bonds, or no triple bonds
Interpretation of Unsaturation Number-----1
1 ring or 1 double bond
Interpretation of Unsaturation Number-----2
2 double bonds, 2 rings, 1 double bond + 1 ring, or 1 triple bond
Interpretation of Unsaturation Number-----3
3 double bonds, 3 rings, 2 double bonds + 1 ring, 2 rings + 1 double bond, 1 triple bond + 1 double bond, or 1 triple bond + 1 ring
Interpretation of Unsaturation Number-4
Interpretation of Unsaturation Number-5
benzene + 1 ring or 1 double bond (4 + 1)
Interpretation of Unsaturation Number-6
benzene + 2 rings, 2 double bonds, 1 double bond + 1 ring, or benzene + 1 triple bond
Nomenclature of Alkenes
The longest continuous carbon chain containing the carbon-carbon double bond is the parent compound.
-Change “-ane” of alkane to “-ene.”
-Number from whichever end that gives the double bond the lowest possible number. Give the location of the double bond. For cycloalkenes, the double bond is assumed to be in the 1 position.
-Use –diene, -triene, and –tetraene, etc if multiple double bonds are present.
-Name and number substituents.
If alkenes are substituents, use the following
Cis and trans
cis – same group, same side
trans – same group, different sides
E and Z – according to Cahn-Ingold-Prelog rules.
Z – high priority same side
E – high priority different sides