(S)-2-butanol

Definition

(S)-2-butanol is a chiral alcohol with the (S) stereochemical configuration. It is one of the four possible stereoisomers of 2-butanol, which is a secondary alcohol with the molecular formula C4H10O.

5 Must Know Facts For Your Next Test

1. The (S) configuration of (S)-2-butanol indicates that the hydroxyl group is on the same side as the higher-priority substituent when the molecule is drawn in the Fischer projection.
2. The other three stereoisomers of 2-butanol are (R)-2-butanol, (R,R)-2,3-butanediol, and (S,S)-2,3-butanediol.
3. Achiral alkenes, such as 2-butene, can undergo addition reactions with water to form chiral alcohols like (S)-2-butanol.
4. The stereochemistry of the product in an addition reaction to an achiral alkene is determined by the Markovnikov rule and the stereochemistry of the water molecule.
5. The presence of a chiral center in (S)-2-butanol leads to the molecule having different physical and chemical properties compared to its enantiomer, (R)-2-butanol.

Review Questions

• Explain the relationship between the (S) configuration of (S)-2-butanol and its stereochemistry.
  • The (S) configuration of (S)-2-butanol indicates that the hydroxyl group is on the same side as the higher-priority substituent when the molecule is drawn in the Fischer projection. This means that the stereochemistry of the chiral center in (S)-2-butanol is the (S) configuration, which is one of the two possible stereochemical arrangements for a secondary alcohol with a chiral center.
• Describe how the addition of water to an achiral alkene, such as 2-butene, can result in the formation of chiral alcohols like (S)-2-butanol.
  • The addition of water to an achiral alkene, such as 2-butene, is an example of a reaction with stereochemistry. The stereochemistry of the product is determined by the Markovnikov rule, which states that the hydrogen atom from the water molecule will add to the carbon atom that can best stabilize the resulting carbocation intermediate. This, combined with the stereochemistry of the water molecule, leads to the formation of a chiral alcohol product, such as (S)-2-butanol, with a specific stereochemical configuration.
• Analyze how the presence of a chiral center in (S)-2-butanol affects its physical and chemical properties compared to its enantiomer, (R)-2-butanol.
  • The presence of a chiral center in (S)-2-butanol means that it is a stereoisomer of (R)-2-butanol, and they are non-superimposable mirror images of each other. As a result, (S)-2-butanol and (R)-2-butanol have the same chemical formula and connectivity, but they differ in their three-dimensional arrangement of atoms. This difference in stereochemistry leads to (S)-2-butanol and (R)-2-butanol having distinct physical and chemical properties, such as their ability to rotate plane-polarized light in opposite directions, their interactions with other chiral molecules, and potentially their reactivity in certain chemical reactions.

Related terms

Stereoisomers:

Stereoisomers are molecules that have the same molecular formula and connectivity, but differ in the three-dimensional arrangement of their atoms.

Chirality:

Chirality is a geometric property of certain molecules and ions that have a non-superimposable mirror image, meaning they cannot be oriented to be identical.

Enantiomers:

Enantiomers are a pair of stereoisomers that are non-superimposable mirror images of each other, and have the same chemical and physical properties, except for their ability to rotate plane-polarized light in opposite directions.