Organic Chemistry: Stereochemistry, Enantiomers, and Chirality Properties

What are the properties of enantiomers?

Same boiling point, melting point, and density; same refractive index; rotate polarized light in opposite directions; different interactions with chiral molecules.

What is optical activity?

The ability of enantiomers to rotate the plane of polarized light in opposite directions but by the same number of degrees.

What is a polarimeter used for?

To measure the rotation of polarized light caused by optically active substances.

What does dextrorotatory mean?

A substance that rotates plane-polarized light clockwise, denoted as (+).

What does levorotatory mean?

A substance that rotates plane-polarized light counterclockwise, denoted as (-).

What is a racemic mixture?

A mixture containing equal quantities of d- and l-enantiomers, resulting in no optical activity.

How can you determine chirality in conformers?

If equilibrium exists between two chiral conformers, the molecule is not chiral; judge chirality by the most symmetrical conformer.

What is a Fischer projection?

A flat representation of a 3-D molecule where a chiral carbon is at the intersection of horizontal and vertical lines.

What are the Fischer rules for drawing projections?

The carbon chain is on the vertical line, and the highest oxidized carbon is at the top.

What happens when you rotate a Fischer projection 180°?

It is allowed and does not change the configuration.

What happens when you rotate a Fischer projection 90°?

It changes the orientation of the horizontal and vertical groups, which is not allowed.

What are diastereomers?

Stereoisomers that are not mirror images of each other.

What are the properties of diastereomers?

They have different physical properties and can be easily separated, unlike enantiomers.

What is a meso compound?

A molecule containing chiral centers and a plane of symmetry, making it achiral.

How do you determine the maximum number of stereoisomers?

Using the formula 2^n, where n is the number of chiral carbons, but consider symmetry for meso compounds.

What is the significance of chirality in taste and smell?

Taste buds and scent receptors are chiral, and enantiomers may have different smells.

What is the role of active sites of enzymes in relation to enantiomers?

Active sites are selective for specific enantiomers, affecting biochemical reactions.

What is the difference between enantiomers and diastereomers in terms of separation?

Enantiomers are difficult to separate; converting them into diastereomers makes separation easier.

What is the notation for racemic mixtures?

It can be denoted as (d,l) or (±).

What is the significance of specific rotation in optical activity?

It depends on the length of the cell, concentration, strength of optical activity, temperature, and wavelength of light.

What is the relationship between diastereomers and cis-trans isomers?

Cis-trans isomers are diastereomers because they are not mirror images of each other.