Chapter 4, Problem 84P

(a)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.

(b)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

For Fischer projection formula: Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is bonded in horizontal line, then the configuration is assigned as just reverse.

(c)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.

Pair of enantiomers has different optical activity, which means if one will show levorotatory then the other will show dextrorotatory.

(d)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.

Pair of enantiomers has different optical activity, which means if one will show levorotatory then the other will show dextrorotatory.

(e)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.

Newman projection: Newman projection of molecule is one type of representations for the alkanes, where the projection visualization from one carbon to another carbon.  In this Newman projection, front carbon which represented as dot is called proximal and the back carbon which represented as circle is called distal.

From the angle of observer the front carbon is proximal and second carbon is distal.

In wedge-dash line representation wedge is coming out of the plane and going behind the plane, the wedge and the dash of front carbon in Newman projection are pointing up and the wedge and the dash of back carbon in Newman projection are pointing down.

(f)

Interpretation Introduction

Interpretation:

The configuration of given structure of 2-chlorobutane has to be determined as (S) or (R).

Concept introduction:

The pair of Enantiomers has different configurations.

Enantiomers are named by following Cahn-Ingold-Prelog system, in which R or S letter is used to differentiate between enantiomers.

According to Cahn-Ingold-Prelog system,

The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center.  The higher the atomic number of atom, higher the priority.  If there is tie, then consider the next atoms attached to the connected atom and so on.

Check the direction of arrow drawn in the direction of decreasing priority.  If the arrow points clockwise direction, then the compound has R configuration.  If the arrow points counterclockwise direction, then the compound has S configuration.  If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.

Newman projection: Newman projection of molecule is one type of representations for the alkanes, where the projection visualization from one carbon to another carbon.  In this Newman projection, front carbon which represented as dot is called proximal and the back carbon which represented as circle is called distal.

From the angle of observer the front carbon is proximal and second carbon is distal.

In wedge-dash line representation wedge is coming out of the plane and going behind the plane, the wedge and the dash of front carbon in Newman projection are pointing up and the wedge and the dash of back carbon in Newman projection are pointing down.