How do we determine #D# and #L# terms, and how do they relate to absolute configuration?
We know that the
for D or L form 1st of all draw the Standard Fischer projection of the molecule.
Standard Fischer projection is that which have its principle chain on the vertical line and the principle group at the top.
for making the same,
- remember, you can do only EVEN NUMBER of changes at a
#color(red) (PARTICULAR#chiral center , otherwise the molecule will optically
now, in the Fischer, look the configuration at bottommost chiral carbon. If H is in left, than it is D form, but if in right than it is L form.
For R and S , 1st of all asign number(1,2,3,4) to the groups attached to chiral center according to the 'CIP rule' which says that
number of a group
attached to the chiral center)
*if two groups are attached to the chiral centre with similar atom (here shown 'C' at 2,3 )than compare the mass of the atom next to them.
Now, after numbering, check that the lowest number is farthest from you which can be done by putting it on the 'dash'( in dash wedge configuration) or on vertical line(in fischer projection) but remember
you can do only EVEN NUMBER of changes at a
now, considering whole as planar, WALK from
( i.e. the way you move your hand when write R and S)
the shown molecule is in R configuration.