Stereochemistry

• How do constitutional isomers differ from stereoisomers in terms of atom connectivity?


  Constitutional isomers have different atom connectivities, while stereoisomers have the same atom connectivities

  
• What are the two main types of stereoisomers and how do they differ?

  • Enantiomers: Non-superimposable mirror images
  • Diastereomers: Non-superimposable stereoisomers that are not mirror images

  
• What characterizes enantiomers?


  They are non-superimposable mirror images

  
• What is the difference between diastereomers and enantiomers?

  Diastereomers are non-superimposable non-mirror images, while enantiomers are non-superimposable mirror images

  
• Why can diastereomers have different physical properties despite having the same molecular formula and atom connectivity?

  Because they have different spatial arrangements of atoms or groups

  
• What are the key differences between enantiomers and diastereoisomers?

  • Enantiomers:
  • Same formula
  • Same connectivity
  • Different arrangement
  • Mirror images

  
  

  • Diastereoisomers:
  • Same formula
  • Same connectivity
  • Different arrangement
  • Not mirror images

  
• What do enantiomers share in terms of chemical formulas and connectivity?


  Enantiomers have the same formula and the same connectivity.

  
• How do the arrangements of atoms differ in enantiomers?

  Enantiomers have different arrangements of atoms around chiral centers.

  
• What is the relationship between enantiomers?

  Enantiomers are mirror images of each other.

  
• What are constitutional isomers?

  Isomers that have different atom connectivities

  
• How do the arrangements of atoms differ in diastereoisomers?

  Diastereoisomers have different arrangements of atoms around chiral centers.

  
• What do diastereoisomers have in common?

  Diastereoisomers have the same chemical formula and same connectivity.

  
• Are diastereoisomers mirror images of each other?


  No, diastereoisomers are not mirror images of each other.

  
• What are the two main types of isomerism?

  Structural isomerism and stereoisomerism

  
• What distinguishes structural isomerism from stereoisomerism?

  • Structural isomerism involves different bonding patterns
  • Stereoisomerism involves different spatial arrangements of atoms

  
• What are the three types of structural isomerism?

  Carbon chain isomerism, positional isomerism, functional group isomerism

  
• How does carbon chain isomerism work?

  • Different branching patterns of the carbon chain
  • Same molecular formula but different structural formulas

  
• How does positional isomerism differ from carbon chain isomerism?

  • Positional isomerism involves different positions of a functional group on the same carbon chain
  • Carbon chain isomerism involves different branching patterns of the carbon chain

  
• What defines functional group isomerism?

  • Same molecular formula
  • Different functional groups

  
• What is tautomerism?


  An isomerisation reaction where there is an interconversion between different functional groups through the movement of hydrogen atoms

  
• What are the two types of stereoisomerism?

  E/Z isomerism and R/S isomerism

  
• What is E/Z isomerism and when does it occur?

  • Occurs in molecules with carbon-carbon double bonds
  • E and Z isomers have the same molecular formula and structural formula
  • Different spatial arrangements due to restricted rotation about the double bond

  
• How does R/S isomerism arise?

  • Molecules with chiral centers (carbon atoms with four different groups)
  • Enantiomers (R and S isomers) are mirror images of each other
  • Different spatial arrangements around the chiral center

  
• What distinguishes E/Z isomers from R/S isomers?

  • E/Z isomers have restricted rotation about a double bond, while R/S isomers have different arrangements around a chiral center
  • E/Z isomers are geometric isomers, while R/S isomers are enantiomers

  
• What are diastereomers?


  Stereoisomers that are not mirror images of each other

  
• How can you identify a chiral molecule?

  • Look for carbon atoms with four different groups attached

  
• What type of carbohydrate projection is shown in the image?

  Fischer projection

  
• What are Fischer projections used to represent?

  • Three-dimensional structures of monosaccharides
  • They show the stereochemistry of the molecule by placing functional groups along horizontal and vertical lines

  
• Name the three monosaccharides shown in the Fischer projections.

  • D-Glucose
  • D-Galactose
  • D-Fructose

  
• How are D-glucose and D-galactose related?

  They are epimers, differing by one chiral center.

  
• How are D-glucose and D-fructose related?

  They are isomers, with different structural formulas.

  
• What are the first three groups in D-glucose, starting from the top?

  • CHO
  • H
  • OH

  
• What are the last two groups in D-glucose?

  H and CH₂OH

  
• What is the first group in D-glucose?

  CHO (aldehyde group)

  
• What functional groups are present in D-glucose?

  • Aldehyde group (CHO)
  • Hydroxyl groups (OH)

  
• What are the first three groups in D-galactose, starting from the top?

  • CHO
  • H
  • OH

  
• How does the fourth group in D-glucose compare to D-galactose?

  In D-glucose, the fourth group is OH, whereas in D-galactose, it is H.

  
• How does the structure of D-fructose differ from D-glucose and D-galactose?

  • D-fructose is a ketose sugar with a ketone group on the second carbon
  • D-glucose and D-galactose are aldose sugars with an aldehyde group on the first carbon

  
• What is the top group in D-fructose?

  CH₂OH

  
• What type of isomerism do D-glucose, D-galactose, and D-fructose exhibit?

  • Isomerism type: Structural isomerism (different structural formulas)