CHM 2110 NOTES 9.20.13
When a carbon has 4 different groups to it, it has chirality because the mirror images
are not superimposable to each other. All physical properties of the mirror images are
the same except for the interactions between the enzymes.
R & S System: clockwise is “rectus,” which is R. Counter-clockwise is “sinister,”
which is S.
o Lowest group is at the bottom of the Fischer projection.
o The highest group is at the top.
o The second highest group is counterclockwise of the top group, to the left.
o The third highest group is clockwise of the top group, to the right.
Rules for Fisher diagram when “H” is not at the bottom.
1. Hold one group steady rotate other 3.
2. Disallowed operations: