Chapter 8, Problem 8.69SP

(a)

Interpretation Introduction

To determine: The type of reaction that fumarase catalyze.

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes are tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. The type of reaction that fumarase catalyze is to be predicted.

Concept introduction: The general steps followed by hydration reaction are stated below:

• First protonation of the alkene take place to generate the carbocation.
• Formation of protonated alcohol.
• Deprotonation.

(b)

Interpretation Introduction

To determine: If fumaric acid and malic acid is chiral and the product, malic acid is optically active or not.

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes are tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. Fumaric acid and malic acid is chiral and the product, malic acid is optically active or not is to be predicted.

Concept introduction: Chiral carbon is an “asymmetric carbon that is attached to four different types of atoms.” Due to asymmetric carbon, they do not posses plane of symmetry and are optically active compounds.

(c)

Interpretation Introduction

To determine: If the given reaction is precede in the laboratory using sulphuric acid as the catalyst, the product will be optically active.

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes are tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. If the given reaction is precede in the laboratory using sulphuric acid as the catalyst, the product will be optically active or not is to be predicted.

Concept introduction: Optically active compounds are the compounds, which posse’s asymmetric carbon or chiral carbon. They can rotate plane polarised light in anticlockwise direction.

(d)

Interpretation Introduction

To determine: The fumarase enzyme is to be a chiral molecule or not.

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes are tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. The fumarase enzyme is to be a chiral molecule or not is to be predicted.

Concept introduction: Chiral carbon is an “asymmetric carbon that is attached to four different types of atoms.” Due to asymmetric carbon, they do not posses plane of symmetry and are optically active compounds.

(e)

Interpretation Introduction

To determine: The enzyme-catalyzed reaction is a syn or anti addition.

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. The given reaction takes place in ${\text{D}}_{\text{2}}\text{O}$ and only one product is formed. The enzyme-catalyzed reaction is a syn or anti addition is to be predicted.

Concept introduction: Stereochemistry is defined as the arrangement of molecule in three dimensional and its impact on chemical reactions. Anti stereochemistry is the addition of any atom from the opposite faces of the double bond of alkene, whereas syn addition is the addition of atom from the same side.

(f)

Interpretation Introduction

To determine: The fisher projection to show the stereoisomer of deuterated malic acid

Interpretation: The given question stated that many enzymes catalyze reactions are similar to reaction that might be used for organic synthesis. Enzymes tend to be stereospecific in their reactions and asymmetric induction is also common. The given reaction is the part of the tricarboxylic acid cycle of cell respiration and resembles a reaction that might be used in the laboratory but enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid. The conversion of fumaric acid to deuterated malic acid by using hydroboration with ${\text{BD}}_{\text{3}}.\text{THF}$, followed by oxidation with ${\text{D}}_{\text{2}}{\text{O}}_{\text{2}}$ and $\text{NaOD}$. The fisher projection to show the stereoisomer of deuterated malic acid is to be predicted.

Concept introduction: An asymmetric carbon atom is represented as a cross in Fisher projection. The carbon chain is kept along the vertical line. The groups attached asymmetric carbon atoms are arranged according to their configuration in Fisher projection. The enantiomers of a chiral compound can be named with the help of right hand and left hand configuration.