Organic Chemistry

Describes the spatial position of atoms/groups in chiral centers (does not depend on other atoms or groups in a molecule)

Assign priorities using Cahn-Ingold-Prelog rules: 1. rank by atomic number 2. rank by atomic mass 3. Find the first point of difference (repeat A and B) (multiple bonds = multiple atoms)

Right hand rule: 1. Thumb = #4 2. Fingers = #1 3. Curl fingers

Describes the spatial position of atoms/groups relative to other atoms/groups in the molecule (Assign priorities using Cahn-Ingold-Prelog rules, highest priorities on the same side = Z, and highest priorities on the opposite side = E)

Molecules with the same molecular formula but different chemical structures

Isomers with different atomic connectivity and have different chemical/physical properties

Are nonsuperimposable on their mirror images, usually have chiral centers, and are optically active (can rotate plane polarized light)

sp³ hybridized atom bound to four different substituents

d-, or (+)-, clockwise rotation

l-, (0)-, counterclockwise rotation

= alpha(obs) / c x l

alpha(obs) x 100 / rotation per concentration-path length

Isomers with the same atomic connectivity but different spatial arrangements of the atoms

Nonsuperimposable mirror images (chiral), no internal plane of symmetry, have identical physical properties, usually have identical chemical properties, have equal but opposite optical activity, and have opposite absolute configuration at every chiral center

A 50/50 mixture of enantiomers and is optically inactive

Non-superimposable and non-mirror images, have different chemical and physical properties, have different absolute configurations but not all opposite, and have unrelated specific rotations

Epimers, anomers, meso compounds, conformational isomers, and geometric isomers

Diastereomers that differ in absolute configuration at a single chiral center

Epimers of carbohydrates at the anomeric carbon

An optically inactive member of a set of stereoisomers and must have chiral centers and an internal plane of symmetry

Diastereomers that differ in spatial arrangements of atoms about double bonds or rings

Differ in spatial arrangement of atoms by rotation about a single bond and cannot be isolated (identical molecules)

Two atoms and/or groups whose dihedral angle is 60^o, or close to 60^o. In other words, their bonds to the axis of rotation are not aligned and the atoms are all equally spaced from each other

The carbons are aligned so that the hydrogens are lined up with each other. This creates steric hindrance between them

All H atoms are eclipsed and wrong bond angles

All H atoms are staggered and 109.5 bond angles

Are unfavorable and all large substituent must be in the equitorial position