Week 10 - Organic Chemistry II Flashcards
conformation
the different three-dimensional structures that can be adopted - rotation of atoms about single bonds within the same molecule
“eclipsed” structures
eclipsed is not stable, it is a transition state; structures that are ‘eclipsed’ suffer from steric strain (causes electron repulsion)
which conformation will have the lowest energy
the conformation where the two ‘giant CH3’ groups are furthest apart from each other
saturated functional groups
halide, alcohol, ether, amine
geometry of halides
tetrahedral
geometry of alcohols + ethers
bent
geometry of amines
trigonal pyramidal
Halide
X-R when x is any halogen (F, Br, I, Cl)
alcohol
OH
Ether
R-O-R
amine
R-N-R **nitrogens with a double bond are not amino groups
unsaturated functional groups
carbonyl, aldehyde, ketone
aldehyde
R-C=O
|
H
ketone
R-C=O
|
R
carboxyls: carboxylic acid, ester
O=C-OH, O=C-O-C
amide
O=C-N-R2
nitriles
N=-C (triple bond)
skeletal isomers
same chemical formula, different arrangement of carbon atoms
positional isomers
same chemical formula, different position of functional group
functional isomers
same chemical formula, different functional groups
cis vs trans (and E vs Z)
cis (E) = majority of carbon chain on same side
trans (Z) = majority of carbon chain of opposite sides
cis/trans and E/Z are not always the same though, E/Z is based on priority based on highest atomic number
geometric isomers
same chemical formula, same bonding, compounds are cyclic, isomerism is at the double bond, different rotation around the bond (not mirror images)
enantiomers
compounds are mirror images of each other
chiral object
no plane of symmetry and must have a chiral center, all different groups only
enantiomers differ in one physical property…
they are optically active
enantiomers can be classified as…
dextrorotatory or levorotatory
how to name enantiomers
- assign priority from 1-4 based on atomic number
- point the lowest one to the back
- draw a curved arrow to show decreasing order of priority
- R if clockwise
- S if counterclockwise
Diastereomers
same chemical formula, same bonding, compounds are not mirror images of each other
if compounds have the same molecular formula, they are…
isomers
conformational isomer
compounds can become each other by rotating single bonds
