Kaplan - Organic Chemistry Flashcards
Parent chain
Longest carbon chain containing the highest-order functional group
Priority between two chains of equal length
The more substituted chain
Carbon #1
Carbon closest to the highest-priority functional group
Oxidation state
Increases with more bonds to heteroatoms (atoms besides carbon and hydrogen)
Decreases with more bonds to hydrogen
Assigning priority
The more oxidized the carbon is, the higher it has
Numbering rings
Starting at the point of gretest substitution and continuing in the direction that gives the lowest numbers to the highest priority groups
Tie between assigning priority in a molecule with double and triple bonds
In a ring, double bond takes precedence
In a chain, they are tied
Substituents
Functional groups that are not part of the parent chain
Carbon chain substituents
Replace -ane with -yl
Multiple substituents of the same type
Add prefixes, like di-, tri-, and tetra-
Order of substitutents
In alphabetical order (ignoring hyphenated prefixes)
IUPAC nomenclature steps
- Identify the parent chain
- Number the chain
- Name the substituents
- Assign a number to each substituent
- Complete the name
Alkane formula
C_n H_(2n+2)
1-carbon hydrocarbon
methane
2-carbon hydrocarbon
ethane
3-carbon hydrocarbon
propane
4-carbon hydrocarbon
butane
5-carbon hydrocarbon
pentane
6-carbon hydrocarbon
hexane
7-carbon hydrocarbon
heptane
8-carbon hydrocarbon
octane
9-carbon hydrocarbon
nonane
10-carbon hydrocarbon
decane
11-carbon hydrocarbon
undecane
12-carbon hydrocarbon
dodecane
Halogen substituent names
fluoro-
chloro-
bromo-
iodo-
Alkene suffix
-ene
Alkyne suffix
-yne
Two forms of numbers for alkenes and alkynes
2-butene
but-2-ene
Naming alcohols (if highest priority)
Replacing -e in the name of the corresponding alkane with -ol
Naming alcohols (if lowest priority)
Considered a hydroxyl substituents (hydroxy-)
Sample common names for alcohols
Ethanol -> ethyl alcohol
Alcohols with two hydroxyl groups
Diols or glycols
Suffix for alcohols with 2 hydroxyl groups
-diol
Diols with hydroxyl groups on the same carbon
Geminal diols
Diols with hydroxyl groups on adjacent carbons
Vicinal diols
Aldehydes
Carbonyl group with a hydrogen bonded to the carbonyl carbon
Methanal common name
Formaldehyde
Ethanal common name
Acetaldehyde
Propanal common name
Propionaldehyde
Ketones
Carbonyl group in the middle of a carbon chain
Common names of ketones
Listing the alkyl groups in alphabetical order
Carbon adjacent to the carbonyl carbon
Alpha
Carboxylic acids
Both a carbonyl group (C=O) and a hydroxyl group (-OH) on a terminal carbon
Highest priority functional group in MCAT-test nomeclature
Carboxylic acids
Methanoic acid common name
Formic acid
Ethanoic acid common name
Acetic acid
Propanoic acid common name
Propionic acid
Esters
Carboxylic acid where the hydroxyl group is replaced with an alkoxyl group
Formal nomeclature of esters
First name is the alkyl group bonded to the oxygen and second name is the carbonyl cabon chain with a -oate suffix
Amides
Carboxylic acid where the hydroxyl group is replaced by an amino group
Substitutes attached to nitrogen
Added to the prefix of the name with a N- for each one
Anhydride
Two carbonyl carbons separated by an oxygen
Symmetrical anhydride
Name only once
Asymmetrical anhydride
Name both in alphabetical order
Carboxylic acid prefix
carboxy-
Carboxylic acid suffix
-oic acid
Anhydride prefix
alkanoyloxycarbonyl-
Anhydride suffix
anhydride
Ester prefix
alkoxycarbonyl-
Ester suffix
-oate
Amide prefix
carbamoyl- or amido-
Amide suffix
-amide
Aldehyde prefix
oxo-
Aldehyde suffix
-al
Ketone prefix
oxo- or keto-
Ketone suffix
-one
Alcohol prefix
hydroxyl-
Alcohol suffix
-ol
Alkene prefix
alkenyl-
Alkene suffix
-ene
Alkyne prefix
alkynyl-
Alkyne suffix
-yne
Alkane prefix
alkyl-
Alkane suffix
-ane
Isomer
Same molecular formula but different structures
Structural isomer
Only thing that they share is molecular weight
Constitutional isomer
Only thing that they share is molecular weight
Physical properties
Characteristics of processes that don’t change the composition of matter, such as melting point, boiling point, solubility, odor, color, density
Chemical properties
In regard to the reactivity of the molecule with other molecules and result in changes in chemical composition
Stereoisomers
Same atomic connectivity
Conformational isomers/conformers
Rotation around single bonds
Configurational isomers
Can be interconverted only by breaking bonds
Newmann projection
Molecule is visualized along a line extending through a carbon-carbon bond axis
Staggered conformation
No overlap of atoms along the line of sight
Anti-staggered conformation
Two largest groups are antiperiplanar (in the same plane, but on opposite sides)
Gauche staggered conformation
Two largest groups are 60 degrees apart
Eclipsed conformation
Overlap of atoms along the line of sight
Totally eclipsed conformation
Highest energy state
Two largest groups are directly overlapping
Three factors that lead to ring strain
- Angle strain
- Torsional strain
- Nonbonded strain
Angle strain
Bond angles deviate from their ideal values by being stretched or compressed
Torsional strain
Cyclic molecules must assume conformations that have eclipsed or gauche interactions
Nonbonded strain (van der Waals repulsion)
Non-adjacent atoms or groups compete for the same space
Flagpole interactions in boat conformation
Result of nonbonded strain in boat cyclohexane
Most stable form of cyclohexane
Chair
Axial
Groups which are perpendicular to the plane of the ring
Equatorial
Groups which are parallel to the plane of the ring
Chair flip
One chair form is converted to the other
All axial groups become equatorial and all equatorial groups become axial
Cis
Both groups are located on the same side of the ring
Trans
Both groups are located on the opposite side of the ring
Optical isomers
Enatiomers and diastereomers have different spatial arrangement of groups that affect rotation of plane-polarized light
Two types of configurational isomers
Enatiomers and diastereomers
Chiral object
Its mirror image cannot be superimposed on the orginal object
Lacks an internal plane of symmetry
Chiral center
A carbon atom that is bonded to 4 different substituents and is an asymmetrical core of optical activity
Enatiomers
Two molecules that are nonsuperimposable mirror images of each other
Diastereomers
Chiral and share the same connectivity but are not mirror images of each other
Enatiomer differences
- Optical activity
2. Reactions in chiral environments
Optical activity
Rotation of this plane-polarized light by a chiral molecule
Dextrorotatory
Rotates the plane of polarized light to the right
Labeled (+)
Levorotatory
Rotates the plane of polarized light to the left
Labeled (-)
Specific rotation
Equals the observed rotation in degrees divided by the concentration and the path length
Racemic mixture
Both (+) and (-) enantiomers are present in equal concentrations
No observed optical activity
Diastereomers
Have two or more stereogenic centers and differs at some (but not all) of these centers
Have different chemical and physical properties
Number of stereoisomers
2^n where n equals the number of chiral centers
Cis-trans isomers
Substituents differ in their position around an immovable bond such as a double bond or around a ring structure
Meso compounds
Molecules with chiral centers that has an internal plane of symmetry
Configuration
Spatial arrangement of the atoms or groups in the molecule
Relative configuration
Configuration in relation to another chiral molecule
Absolute configuration
Describes the exact spatial arrangement of these atoms or groups, independent of other molecules
(E) and (Z) forms
- Assign each atom bonded to the double-bonded molecules
- If the two highest priority substituents are on the same size, they are named (Z) - otherwise (E)
(R) and (S) forms
- Assign priority to each atom bonded to the carbon substituents
- Arrange the molecule in space (place the lowest priority in the back)
- Draw a circle from substituent to substituent
- If clockwise, (R)
- If counter-clockwise, (S)
Cahn-Ingold-Prelog priority rules
Higher the atomic number, higher the priority
If there is a tie, go to the next bonded atom
Fischer projection
Horizontal lines indicate bonds that project out from the plane of the page, whereas vertical lines indicate bonds going into the plane of the page
Determing (R)/(S) labeling based on Fischer projection
Make the lowest priority group the top group
Determine chirality based on direction from remaining groups
If you had to rearrange once, the label is the opposite of what you got
If you had to rearrange twice, the label is the opposite of what you got
