Organic Chemistry
Introduction
Functional Groups
Alkanes
Alkenes
Alkynes
Alcohols
Acids, Esters and
Amides
Introduction
 Organic chemistry is the study of carboncontaining compounds
especially compounds containing C-C
bonds
 The field of organic chemistry is very important
for a wide variety of reasons.
A huge number of carbon-containing
compounds are known.
 More than 16 million known compounds
 About 90% of new compounds made each
year contain carbon
Introduction
 Most of the advances in the pharmaceutical
industry are based on a knowledge of
organic chemistry.
Many drugs are organic compounds
 Life as we know it is based on organic
chemistry.
Most biologically important compounds
contain carbon:
 DNA, RNA
 proteins
 carbohydrates
Introduction
 Learning organic chemistry requires you to
integrate and apply many of the concepts
you’ve learned in general chemistry:
Electron configuration
Valence bond theory
Lewis structures
Resonance structures
Hybrid orbitals
Molecular geometry
Acid/base reactions
Oxidation/reduction
Kinetics
Equilibrium
Thermodynamics
Stoichiometry
H O
Introduction
C
C O H
H
H O
H C C O H
 Some
familiar organic compounds:
H
H
H
H C H
H
H H H
H C C C
H
H H H
propane
methane
H O H
H C C H
acetylene
H C C
H
C
H
H acetone
Introduction
 Some familiar organic compounds:
H O
H C C O H
H
Acetic acid
H H
H C C O H
H
H Ethyl alcohol
H H
H H
H C C O C C
H
O
H
H H
“ether”
C OH
aspirin
O
C CH3
O
H
Introduction
 Most organic compounds have a “skeleton”
that is composed of C-C bonds.
 The C-C bonds may be single bonds,
double bonds, or triple bonds.
 The “skeleton” of an organic compound has
H’s attached to it.
other “heteroatoms” like O, halogens or N
may be present as well
Introduction
 The number of bonds formed by C in an
organic compound is determined by the
electron configuration of C.
Carbon has four valence electrons:
1s22s22p2
Introduction
 Carbon generally forms 4 equivalent bonds.
 The formation of four equivalent bonds is
best explained using the concept of hybrid
orbitals.
Introduction
 The structure of an organic compound can
be predicted by drawing a Lewis structure:
H
H
O
H
C
C
C
H
H
H
acetone
Introduction
 In organic molecules, we generally describe
the geometry around each carbon atom.
 Geometry is predicted using:
VSEPR
hybrid orbitals
Introduction
 When C forms four single bonds:
sp3 hybrid orbitals are involved
 tetrahedral geometry
H
H
 When C forms a double bond:
sp2 hybrid orbitals are used
 trigonal planar geometry
 When C forms a triple bond:
sp hybrid orbitals are used
 linear geometry
C
H
C
H
H C C H
Introduction
Example: Identify the electron domain
geometry and hybrid orbitals used by each
atom (except hydrogen) in the following
compound.
H O
H C C C C O H
H
Introduction
 Organic compounds contain not only C-C
bonds but also C-H bonds.
 C-C and C-H bonds tend to be non-polar
because there is a small difference in
electronegativites
 Most (but not all) organic compounds are
relatively non-polar
generally not very soluble in water
Hydrocarbons
 The simplest organic compounds are the
hydrocarbons:
organic compounds that contain only
carbon and hydrogen
four general types:
alkanes
alkenes
alkynes
aromatic hydrocarbons
Hydrocarbons
 Alkanes:
hydrocarbons that contain only single
bonds
 Examples:
Methane
ethane
CH4
H
H
H–C–C–H
H
H
Hydrocarbons
 Alkenes:
hydrocarbons that contain a C = C double
bond
H2C = CH2 (ethylene)
 Alkynes:
hydrocarbons that contain a C
bond
H – C C – H (acetylene)
C triple
Hydrocarbons
 Aromatic hydrocarbons:
contain a planar ring structure in which
the carbon atoms are connected by a
combination of both s and p bonds
H
C
H-C
C-H
H-C
C-H
C
H
benzene
Introduction
 Organic compounds that are soluble in polar
solvents such as water generally have a
polar functional group present in the
molecule.
An atom or group of atoms that influences
the way the molecule functions, reacts or
behaves.
an atom or group of atoms in a molecule
that undergoes predictable chemical
reactions
the center of reactivity in an organic
molecule
Introduction
 Functional groups that contain O or N atoms
often lead to a polar organic molecule
large difference in electronegativity
C vs. O
C vs. N
 Examples of familiar polar organic
compounds:
Functional groups
glucose
contain C-O bonds
acetic acid
Vitamin C
Functional groups contain
amino acids C-O and C-N bonds
Functional Groups
 Since functional groups are responsible for
the many of the chemical and physical
properties of organic compounds, we often
classify and study organic compounds by
the type of functional group present.
 On your exam, you will be responsible for
recognizing and naming the various
common functional groups that are found in
organic compounds:
Functional Groups
Functional Type of
Group
Compound
C=C
alkene
C
alkyne
C
Example
H2C = CH2
HC
CH
C–O–H
alcohol
CH3OH
C–O–C
ether
CH3CH2OCH2CH3
C–N
amine
CH3NHCH3
Functional Groups
Functional
Group
Type of
Compound
O
C–H
O
aldehyde
O
C–C–C
Example
CH3C – H
O
ketone
CH3 – C – CH3
Functional Groups
Functional
Group
O
Type of
Compound
Carboxylic
C–O–H
acid
O
C–O–C
Example
O
CH3C – O – H
O
ester
CH3C – O – CH2CH3
Functional Groups
Functional
Group
O
Type of
Compound
C–N–
amide
Example
O
CH3C – N – CH3
H
Functional Groups
Example: Name the functional groups that are
present in the following compounds:
CH3CH2OH
O
H2C = CHCOH
CH3CH2NCH3
CH3
Functional Groups
Example: Name the functional group(s) that is
(are) present in the following compounds:
O
H2C
CH2
H2C
CH2
CH3NHCH2CH2OCH3
Hydrocarbons
 Alkanes are often called saturated
hydrocarbons
they contain the largest possible number
of hydrogen atoms per carbon atom.
 Alkenes, alkynes, and aromatic
hydrocarbons are called unsaturated
hydrocarbons
they contain less hydrogen than an alkane
having the same number of carbon atoms
H H H H
H C C C C H
H
H
H
H
H
Alkanes
H
 Organic compounds can H
be Hrepresented
in
C C H
many different ways:H C C
H H H
H
molecular formula: C4H10H(butane)
H H H
Lewis structure:
H
H
H
H H C HC C C H
C C C C H
H HH
H H
H H H
Condensed structural formula
 CH3CH2CH2CH3
Line angle drawings
Alkanes
Some of the simplest alkanes:
Condensed
Formula
CH4
Name
methane
CH3CH3
ethane
CH3CH2CH3
propane
CH3CH2CH2CH3
butane
CH3CH2CH2CH2CH3
pentane
You must know these!!!
Alkanes
Some of the simplest alkanes:
Condensed
Formula
Name
CH3CH2CH2CH2CH2CH3
hexane
CH3CH2CH2CH2CH2CH2CH3
heptane
CH3CH2CH2CH2CH2CH2CH2CH3
octane
CH3CH2CH2CH2CH2CH2CH2CH2CH3
nonane
CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
decane
You must know these!!!
Alkanes
 The previous alkanes are also called
straight-chain hydrocarbons:
all of the carbon atoms are joined in a
continuous chain
 Alkanes containing 4 or more carbons can
also form branched-chain hydrocarbons
(branched hydrocarbons)
some of the carbon atoms form a “branch”
or side-chain off of the main chain
Alkanes
 An example of a straight chain hydrocarbon:
C5H12 CH3CH2CH2CH2CH3
pentane
 Examples of a branched hydrocarbon:
C5H12 CH3CHCH2CH3
CH3
2-methylbutane
CH3
CH3CCH3
CH3
2,2-dimethylpropane
Alkanes
 The three structures shown previously for
C5H12 are structural isomers:
compounds with the same molecular
formula but different bonding
arrangements
 Structural isomers generally have different
properties:
different melting points
different boiling points
often different chemical reactivity
Alkanes
 Alkanes with three or more carbons can also
form rings or cycles.
 Cycloalkanes:
Alkanes containing a ring structure that is
held together by C – C single bonds
 Examples:
H2C
CH2
CH2
cyclopropane
Alkanes
 Examples of cycloalkanes:
CH2
H2C
CH2
H2C
cyclopentane
CH2
CH2
H2C
CH2
H2C
CH2
CH2
cyclohexane
Alkanes
 Organic compounds can be named either
using common names or IUPAC names.
 You must be able to name alkanes, alkenes,
alkynes, and alcohols with 10 or fewer
carbons in the main chain using the IUPAC
naming system.
Alkanes
 Alkane Nomenclature:
Find the longest continuous chain of
carbon atoms and use the name of the
chain for the base name of the compound:
longest chain may not always be written
in a straight line
1
2
CH3 - CH - CH3
3 CH2 -
CH2 - CH2 - CH3
4
5
6
Base name:
hexane
Alkanes
 Alkane Nomenclature:
Number the carbon atoms in the longest
chain beginning with the end of the chain
closest to a substituent
groups attached to the main chain that
have taken the place of a hydrogen
atom on the main chain
1
A substituent
CH3 -2CH - CH3
3 CH2 -
CH2 - CH2 - CH3
4
5
6
Alkanes
 Alkane Nomenclature:
Name and give the location of each
substituent group
A substituent group that is formed by
removing an H atom from an alkane is
called an alkyl group:
Name alkyl groups by dropping the “ane”
ending of the parent alkane and adding
“yl”
Alkanes
 Alkane Nomenclature:
Common alkyl groups (substituents):
CH3
CH3CH2
CH3CH2CH2
CH3CH2CH2CH2
1
methyl
Know
ethyl
propyl these!
butyl
CH3 -2CH - CH3
3 CH2 -
CH2 - CH2 - CH3
4
5
6
2-methylhexane
Alkanes
 Alkane Nomenclature:
Halogen atoms are another common class
of substituents.
Name halogen substituents as “halo”:
Cl
chloro
Br
bromo
I iodo
Alkanes
 Alkane Nomenclature:
When two or more substituents are
present, list them in alphabetical order:
 Butyl vs. ethyl vs. methyl vs. propyl
When more than one of the same
substituent is present (i.e. two methyl
groups), use prefixes to indicate the
number:
 Di = two
Know these.
 Tri = three
 Tetra = four
 Penta = five
Alkanes
Example: Name the following compounds:
CH3CH2CHCH2CH3
CH3
CH2CH2CH3
CH3CHCHCH3
CH3
Alkanes
Example: Name the following compounds:
CH3CH2CHCH3
CH2CH2Br
CH2CH2CH3
CH3CHCHCH3
Cl
Alkanes
 You must also be able to write the structure
of an alkane when given the IUPAC name.
 To do so:
Identify the main chain and draw the
carbons in it
Identify the substituents (type and #) and
attach them to the appropriate carbon
atoms on the main chain.
Add hydrogen atoms to the carbons to
make a total of 4 bonds to each carbon
Alkanes
Example: Write the condensed structure for
the following compounds:
3, 3-dimethylpentane
3-ethyl-2-methylhexane
2-methyl-4-propyloctane
1, 2-dichloro-3-methylheptane
Alkenes
 Alkenes:
unsaturated hydrocarbons that contain a
C=C double bond
 Alkene Nomenclature:
Names of alkenes are based on the
longest continuous chain of carbon atoms
that contains the double bond.
Alkenes
 Alkene Nomenclature
Find the longest continuous carbon chain
containing the double bond.
Change the “ane” ending from the
corresponding alkane to “ene”
 butane
butene
 propane
propene
 octane
octene
Alkenes
 Alkene Nomenclature
Indicate the location of the double bond
using a prefix number
designate the carbon atom that is part
of the double bond AND nearest to the
end of the chain
Name all other substituents in a manner
similar to the alkanes.
Use a prefix to indicate the geometric
isomer present, if necessary.
Alkenes
 Alkene Nomenclature
 Different geometric isomers are possible for
many alkenes.
Compounds that have the same molecular
formula and the same groups bonded to
each other, but different spatial
arrangements of the groups
cis isomer
trans isomer
Alkenes
 Alkene Nomenclature
Cis isomer:
two identical groups (on adjacent
carbons) on the same side of the C = C
double bond
Trans isomer:
two identical groups (on adjacent
carbons) on opposite sides of the C = C
double bond
Alkene
CH3
CH3
CH3
C=C
H
H
C=C
H
cis-2-butene
H
CH3
trans-2-butene
Alkene
For an alkene with the general formula
A
P
C=C
B
Q
cis and trans isomers are possible only if
A = B and
P=Q
Alkene
Example: Name the following alkenes:
CH3CH2
H
C=C
H
H
CH3CH2
H
C=C
CH3CHCH2
CH3
CH2CH3
Alkenes
Example: Draw the structures for the following
compounds:
2-chloro-3-methyl-2-butene
trans-3, 4-dimethyl-2-pentene
cis-6-methyl-3-heptene
Alkynes
 Alkynes:
unsaturated hydrocarbons that contain a
C C triple bond
 Alkyne Nomenclature:
Identify the longest continuous chain
containing the triple bond
To find the base name, change the ending
of the corresponding alkane from “ane” to
“yne”
Alkynes
 Alkyne Nomenclature:
Use a number to designate the position of
the triple bond
number from the end of the chain
closest to the triple bond
just like with alkenes
Name substituents like you do with
alkanes and alkenes
Alkynes
Example: Name the following compounds:
CH3CH2C
CCHCH3
CH2CH3
CH2CH2C
Cl
CH
Alkynes
Example: Draw the following alkynes.
4-chloro-2-pentyne
3-propyl-1-hexyne