Organic
Organic Chemistry Exam 4
Alkenes o Degrees of Unsaturation – removing hydrogens by
introducing double bonds or ring structures o Unsaturation Number =
number of double bonds, rings, or pi bond systems o To figure out the
unsaturation number...
1. Figure out the maximum number of
hydrogen atoms 2(# of C) + 2
2. Subtract the actual number of
hydrogen atoms
3. Divide by 2 o Example:
H3C C C CH3
1.
2(4) + 2 = 10
2.
10 - 6 = 4 3. 4/2 = 2
o Nomenclature o Cis and trans does
not always work
§ Cis = same
§ Trans = opposite o E and Z does
always work § Meaning:
• E = opposite
• Z = same
§ Assign priorities to the molecules
coming off of each carbon (treat each
carbon separately) § 2 H3C OCH3 1
Example:
1 BrH 2
E
C C 1
BrOCH3
C C
Organic Chemistry Exam 4
, Organic
2 H2
H 3C
Z
Addition Reactions Overview
o Concept o E = electrophile
E Y
PROTON o Y = nucleophile E Y
ELECTRON
o Stereoselectivity o Syn – elements
added on the same side o Anti – elements
added on opposite sides
o Markovnikov’s Rule o You make the more
stable carbocation when possible
§ More substituted carbon with a + charge =
more stable
§ Add H to the least substituted carbon
H
H
-H
OR
more stable
Specific Addition Reactions o Hydrohalogenation o Involves
H-X o Regioselective – add the H to the less substituted carbon
(MARKOVNIKOV) o Stereoselective – syn and anti
H H H H H H H
Cl Cl
H Cl Cl
o Hydration o Involves H2O and often H2SO4 o An alcohol
is formed o Regioselective – add the H to the less
substituted carbon (MARKOVNIKOV) o Stereoselective –
syn and anti
O
Organic Chemistry Exam 4
Organic Chemistry Exam 4
Alkenes o Degrees of Unsaturation – removing hydrogens by
introducing double bonds or ring structures o Unsaturation Number =
number of double bonds, rings, or pi bond systems o To figure out the
unsaturation number...
1. Figure out the maximum number of
hydrogen atoms 2(# of C) + 2
2. Subtract the actual number of
hydrogen atoms
3. Divide by 2 o Example:
H3C C C CH3
1.
2(4) + 2 = 10
2.
10 - 6 = 4 3. 4/2 = 2
o Nomenclature o Cis and trans does
not always work
§ Cis = same
§ Trans = opposite o E and Z does
always work § Meaning:
• E = opposite
• Z = same
§ Assign priorities to the molecules
coming off of each carbon (treat each
carbon separately) § 2 H3C OCH3 1
Example:
1 BrH 2
E
C C 1
BrOCH3
C C
Organic Chemistry Exam 4
, Organic
2 H2
H 3C
Z
Addition Reactions Overview
o Concept o E = electrophile
E Y
PROTON o Y = nucleophile E Y
ELECTRON
o Stereoselectivity o Syn – elements
added on the same side o Anti – elements
added on opposite sides
o Markovnikov’s Rule o You make the more
stable carbocation when possible
§ More substituted carbon with a + charge =
more stable
§ Add H to the least substituted carbon
H
H
-H
OR
more stable
Specific Addition Reactions o Hydrohalogenation o Involves
H-X o Regioselective – add the H to the less substituted carbon
(MARKOVNIKOV) o Stereoselective – syn and anti
H H H H H H H
Cl Cl
H Cl Cl
o Hydration o Involves H2O and often H2SO4 o An alcohol
is formed o Regioselective – add the H to the less
substituted carbon (MARKOVNIKOV) o Stereoselective –
syn and anti
O
Organic Chemistry Exam 4
