STEREOISOMERISM CREDITS TO THE OWNER OF THE PIC

1. STEREOISOMERISM
GROUP2

2. OBJECTIVES
• Define the Stereoisomerism
• Difference of reducing and non-reducing
sugars
• What is a reducing and non-reducing
sugars

3. What is stereoisomerism?
• Are isomers that have the same molecular and structural formulas but
differ in the orientation of atom in space. By contrast, atoms are
connected to each other in different ways in constitutional isomers.
• Defined in an earlier introductory section, isomers are different
compounds that have the same molecular formula.
• Stereoisomers are isomers that have the same composition.
• Came from the Greek word "isos" and "meros'' which means equal
part, the term is coined by Swedish chemist Jacob Berzelius (1830)

4. MAJORS STRUCTURAL FEATURES THAT
GENERATE STEREOISOMERISM:
1. The presence of a chiral center in a molecule.
2. The presence of ‘structural rigidity’ I a
molecule.

5. Two division of Stereoisomers:
• Enantiomers
• Are stereoimers whose molecules are
nonsuperimposable mirror images of each other. Left-
and-right-handed forms of a molecule with a single chiral
center are enantiomers

6. • Diastereomers
- are stereoisomers whose molecules are not mirror images of each other.
- Example: Alkene and Cycloakane.
Two or more stereocenter.
can include compounds that are ring structures.
Consider two compounds with a six-membered ring that have two
substituents each . Example a clorine atom and an ethyl group.

7. Ring structure compounds:

8. Do the molecules have
the same molecular
formula?
NO YES
The molecules
are NOT
isomers
molecules are
ISOMERS
Are the atoms
bonded in the
same order in the
two molecules?
YES NO
The molecules
are
CONSTITUTION
AL ISOMERS
The molecules are
STEREOISOMERS.
Are the molecules
NONSUPERIMPOSABLE
MIRROR IMAGE?
The molecules are
ENANTIOMERS
The molecules are
DIASTEREORISM
YES NO

9. REDUCING AND NONREDUCING SUGARS
• Monosaccharide are example of reducing sugars.
• All monosaccharide such as glucose are reducing sugars. A disaccharide can be a
reducing sugar or non-reducing sugar. Maltose and lactose are reducing sugars .
• You can identify a sugar by looking for the anomeric carbon.
• Anomeric carbon is the first stereocenter of the molecule.
• If that stereocenter has an OH group coming off of it then it is reducing sugar.
• Purpose of Reducing sugars:
• The most important monosaccharide is glucose, because is known as blood sugars
and it is essential for brain function and physical energy.

10. WHY IS REDUCING SUGARS IMPORTANT IN
HUMANS?
• It is important in maintaining human life by creating an energy source for the body.
• NON-REDUCING SUGARS do not have an OH group attached to the anomeric carbon so
they cannot reduce other compounds
• It is a sugar that cannot donate electrons to other molecules.
• SUCROSE is an example of non-reducing sugars.
• Other examples are TREHALOSE,RAFFINOSE, STACHYOSE AND VERBASCOSE.

11. IS STARCH A NON-REDUCING SUGARS?
• Starch is not a reducing sugar. The first ring cannot open up because there’s no hydrogen on
the circled oxygen.
• Polysaccharide such as starch are not reducing sugars.
STARCHY FOODS

12. Sucrose:(non-reducing sugars)
Glucose: (reducing sugars)

13. Maltose: Reducing Sugars
Lactose: Reducing Sugars