single bond sp hybrid
10g reality
1200 on paper
L
double bond sp hybrid
1200 reality
120 on paper
triple bond sp hybrid
1800reality
1800 on paper
Number of
C Name If not part of the longest chain
i e Substituent naming goes
as
1 Methane follows
2 Ethane methyl F Fluoro
ethyl CL
3 Propane propyl Chloro
Butyl
4 Butane Pentyl Br Bromo
Hexyl
5 Pentane Heptyl I todo
Oct L
Hexane
7 Heptane Bonding takes priority when numbering
8 Octane
3 methyl but 1 ene
µ
, E or Z geometry according to CIP nomenclature
I l
w t
I f l
z 3 methylpent 2 ene E 3 methylpent 2 ene
compound with circle structure
Have cyclo prefix i e D cyclobutane
D cyclopropane
Numbering starts alphabetically
Br 1 bromo 3 iodocyclohexane
R and S configuration
Lowest CIP priority points AWAY
F3 f f's
f B I Hy
Amu
H
Da
Ch
Tt
NEi
H4
Z y
Br Br Ct
y z
T 2
The order in which priorities 1,2 and 3 are determines
naming
anticlockwise S
clockwise R
,As with E and 2 if a tie move to the next atom
CL 4
Two to draw
ways
pj
H
F J Or o Draw a mirror image
3 2 o
Invert all Stereogenic centres
Cl
Wh
Ba
F
,Double bond Alkene geometry
simplest way to separate similar structures by cis and trans
naming
cis same e.g
trans opposite
A
trans but 2 ene cis but 2 ene
For more complex molecules Cahn Ingold Prelog Clp Priority is used
1 Cut alkene in half from the doublebond
2 See atoms connected to sp carbon
l
f f
o
3
with
1 Priority PER SIDE
highest molar
goes to the atom
mass
0 4 Name it
i
0 I
1 Z 3 methylpent 2 ene
2 same side
E opposite side
, Isomerism
SAME molecular formula
Isomers
Constituitional isomers
same connectivity
different connectivity different spatial
same atoms still arrangement geometry
Stereoisomerism
central C with 4
different bonds Usually lost
with structural
Enantiomers come in pairs formula
1
loss
Identical physical of
properties E
mirror images IZ
NMR of each other information
effigy Nont
superimposable
Boiling
density
ALL
stereocenters
are a.k.a Optical isomers
inverted
Diastereomers
Non superimposable
similar to enantiomers
Not mirror images HOWEVER
some but NOT ALL stereocenters
are inverted
, Newman Projections
Can be aligned to rotatable sp bond
The sawhorse method
F F Ctb ch Ctb ch
f
Hsc K H 7 H
J
Algorithm perspective
J
F
H Ctf Ch
Liga
1 0001
H
CHz a
t
H
Looking from the LEFT
dashes will be on the LEFT
H CL
CHz
AND
H F
Hz
T
CH
H c
H F
cuz
, Conformation
staggered 1800 substituents far away from each other
H H Most stable
H
I H
Eclipsed O substituents close to each other
y Least stable
y
H
H
1 I H
transition state
Gauche 600 Local minimum
H u 2nd most stable
l
H I H
H
The energies explain why we draw molecules the way we
do
We can identify enantiomers using Newman Projections
also
Compare the front part of two molecules
Compare the back part of two molecules
If both are mirror images of each other Enantiomer
If only one is a mirror image diastereomer
, Resonance and curly arrows
Born Oppenheimer approximation allows us to consider electron
separately from nuclei
Electrons more t
Changes re bond only
Atoms move w
changes o bond
Changes atom geometry hybridisation
Resonance only affects R bonds and can sometimes offer
extra stability
Movement of electrons only
Charge and resonance
empty p
Yo 888 2 half filled P's
to make it bond
8880888
Double headed arrow Resonance arrows
Electron movement only
Electrons moving due to resonance structure are called
delocalised electrons
10g reality
1200 on paper
L
double bond sp hybrid
1200 reality
120 on paper
triple bond sp hybrid
1800reality
1800 on paper
Number of
C Name If not part of the longest chain
i e Substituent naming goes
as
1 Methane follows
2 Ethane methyl F Fluoro
ethyl CL
3 Propane propyl Chloro
Butyl
4 Butane Pentyl Br Bromo
Hexyl
5 Pentane Heptyl I todo
Oct L
Hexane
7 Heptane Bonding takes priority when numbering
8 Octane
3 methyl but 1 ene
µ
, E or Z geometry according to CIP nomenclature
I l
w t
I f l
z 3 methylpent 2 ene E 3 methylpent 2 ene
compound with circle structure
Have cyclo prefix i e D cyclobutane
D cyclopropane
Numbering starts alphabetically
Br 1 bromo 3 iodocyclohexane
R and S configuration
Lowest CIP priority points AWAY
F3 f f's
f B I Hy
Amu
H
Da
Ch
Tt
NEi
H4
Z y
Br Br Ct
y z
T 2
The order in which priorities 1,2 and 3 are determines
naming
anticlockwise S
clockwise R
,As with E and 2 if a tie move to the next atom
CL 4
Two to draw
ways
pj
H
F J Or o Draw a mirror image
3 2 o
Invert all Stereogenic centres
Cl
Wh
Ba
F
,Double bond Alkene geometry
simplest way to separate similar structures by cis and trans
naming
cis same e.g
trans opposite
A
trans but 2 ene cis but 2 ene
For more complex molecules Cahn Ingold Prelog Clp Priority is used
1 Cut alkene in half from the doublebond
2 See atoms connected to sp carbon
l
f f
o
3
with
1 Priority PER SIDE
highest molar
goes to the atom
mass
0 4 Name it
i
0 I
1 Z 3 methylpent 2 ene
2 same side
E opposite side
, Isomerism
SAME molecular formula
Isomers
Constituitional isomers
same connectivity
different connectivity different spatial
same atoms still arrangement geometry
Stereoisomerism
central C with 4
different bonds Usually lost
with structural
Enantiomers come in pairs formula
1
loss
Identical physical of
properties E
mirror images IZ
NMR of each other information
effigy Nont
superimposable
Boiling
density
ALL
stereocenters
are a.k.a Optical isomers
inverted
Diastereomers
Non superimposable
similar to enantiomers
Not mirror images HOWEVER
some but NOT ALL stereocenters
are inverted
, Newman Projections
Can be aligned to rotatable sp bond
The sawhorse method
F F Ctb ch Ctb ch
f
Hsc K H 7 H
J
Algorithm perspective
J
F
H Ctf Ch
Liga
1 0001
H
CHz a
t
H
Looking from the LEFT
dashes will be on the LEFT
H CL
CHz
AND
H F
Hz
T
CH
H c
H F
cuz
, Conformation
staggered 1800 substituents far away from each other
H H Most stable
H
I H
Eclipsed O substituents close to each other
y Least stable
y
H
H
1 I H
transition state
Gauche 600 Local minimum
H u 2nd most stable
l
H I H
H
The energies explain why we draw molecules the way we
do
We can identify enantiomers using Newman Projections
also
Compare the front part of two molecules
Compare the back part of two molecules
If both are mirror images of each other Enantiomer
If only one is a mirror image diastereomer
, Resonance and curly arrows
Born Oppenheimer approximation allows us to consider electron
separately from nuclei
Electrons more t
Changes re bond only
Atoms move w
changes o bond
Changes atom geometry hybridisation
Resonance only affects R bonds and can sometimes offer
extra stability
Movement of electrons only
Charge and resonance
empty p
Yo 888 2 half filled P's
to make it bond
8880888
Double headed arrow Resonance arrows
Electron movement only
Electrons moving due to resonance structure are called
delocalised electrons
