Chapter 4.9, Problem 32P

Interpretation Introduction

Interpretation:

The configuration of (+)-2-methyl-1-butanol has to be determined from the given structure of (-)-2-methyl-1-butanol.

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.