Organic Chemistry I Concepts
Common Functional Groups
Functional Group Name
F, Cl, Br, or I
Example
Alkane
CH3CH2CH3 (propane)
Alkene
CH3CH=CH2 (propene)
Alkyne
CH3C CH (propyne)
Alkyl halide CH3Br (methyl bromide)
Alcohol
CH3CH2OH (ethanol)
Ether
CH3OCH3 (dimethyl ether)
Amine
CH3NH2 (methyl amine)
Functional Groups That Contain a Carbonyl
Functional Group Name
Example
Aldehyde
CH3CHO (acetaldehyde)
Ketone
CH3COCH3 (acetone)
Acyl chloride
CH3COCl (acetyl
chloride)
Carboxylic acid CH3CO2H (acetic acid)
CH3CO2CH3 (methyl
acetate)
Ester
Typical Oxidation Numbers of Carbon
Functional Group Example
Oxidation Number of
Carbon in the Example
Alkane
CH4
-4
Alkyllithium
CH3Li
-4
Alkene
H2C=CH2 -2
Alcohol
CH3OH
Ether
CH3OCH3 -2
Alkyl halide
CH3Cl
-2
Amine
CH3NH2
-2
Carboxylic acid
HCO2H
2
-2
Other Terms:
α-carbon - The carbon adjacent to the leaving group .
Backside Attack - The SN2 mechanism in which the nucleophile attacks the α-carbon from a direction directly
opposite to the C-LG bond. Results in inversion of stereochemical configuration.
Bimolecular - Involving two molecules. In this SparkNote, the term bimolecular is used to refer to SN2 and E2
reactions. The rate-limiting transition states of both reactions involve two molecules.
Carbocation - A carbon that carries a positive charge. Carbocations are highly unstable and are prone to
rearrangement. SN1 and E1 reactions proceed through a common carbocation intermediate.
Frontside attack - A disproved SN2 mechanism in which the nucleophile attacks the α- carbon from the same side
as the C-LG bond. If this mechanism was valid, it would result in retention of stereochemical configuration. See
backside attack.
Rate law - A mathematical equation that relates the rate of a reaction to the concentration of its reactants. For a
generic reaction:
X+Y→Z
The rate law is expressed as:
rate = k [X]a [Y]b
Rate-limiting step - The slowest step in a reaction that determines the overall rate.
Reaction order - In the rate law, the value of "a" and "b" for reactants "X" and "Y," respectively. The overall order of
a reaction is the sum of "a" and "b" and tells how many molecules of reactant are involved in the transition state of the
rate-limiting step.
Reaction intermediate - An intermediary molecule that accumulates in negligible quantities during a reaction.
SN2 - A SN2 reaction is a bimolecular (2 molecules) reaction involving the Substitution of a Nucleophile for a leaving
group.
SN1 - A reaction in which a Nucleophile Substitutes for a leaving group. SN1. It goes through a carbocation
intermediate.
Secondary - A secondary carbon has bonds to two other carbons.
Tertiary - A tertiary carbon has bonds to three other carbons.
Transition state - An extremely unstable molecule that forms between the reactants and their
intermediates/products. A transition state exists at the peaks of an energy diagram, in contrast to intermediates and
products, which form in the troughs.
Practice Problems:
#1.
Identify the common functional groups in each compound.
#2
#3 Which compound is not a member of the alkene series? (1) benzene; (2) acetylene;
(3) toluene; (4) ethane
#4 Which is the correct molecular formula of pentene? (1) C5H8; (2) C5H10; (3) C5H12;
(4) C5H14
#5 C2H4 + H2 <======> C2H6 The above reaction is an example of (1) addition;
(2) substitution; (3) saponification; (4) esterification.
#6
3
Answers:
#1. All three compounds are aromatic. Aspirin is also a carboxylic acid ( CO2H) and an ester (
CO2CH3). Tylenol is also an alcohol ( OH) and an amide ( CONH ). Ibuprofen
contains alkane substituents and a carboxylic acid functional group.
#2
#3 ethane
#4 C5 H10
#5 addition
#6
1) Electron donatin major product: para, minor product: ortho
2) Electron withdrawing Major product: meta
3) –CH2CH3 Electron donating
-NO2 Electron withdrawing
Major product: ortho position to –CH2CH3