Chapter 4.8, Problem 27P

Interpretation Introduction

Interpretation:

The given compound has to be drawn in perspective formula.

Concept introduction:

Perspective formula: draw two bonds of asymmetric carbon is in plane, one bond as a solid wedge that coming out of plane and the fourth bond as hatched wedge that pointing away from the plane.  The solid wedge is always below to the hatched wedge.

Fischer projections: the asymmetric center (carbon) represents as the point of intersection of two perpendicular lines, in which the horizontal lines represent the bonds that project out of the plane of the paper and the vertical lines represent the bonds that away from the plane of the paper.

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. I f there is tie, then consider the next atoms attached to the connected atom and so on.

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

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.