IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

kbanagar

pls read the following carefully...............

R (rectus means right) and S(sinister means left) NOTATIONS

this sys of notations was devised by cahn , ingold & prelog.

RANK THE GROUPS [atoms] which r bonded to the chirality centre in the order of the priority.

the priority list is
I>Br>Cl>SO₃H>F>OCOR>OR>OH>NO₂>NHCOR>NHR>NH₂>CCl₃>COCl>
COOR>COOH>CONH₂>COR>CHO>CH₂OH>CN>C₆H₅>CR₃>CHR₂>CH₂R>CH₃

THE RULES ARE AS FOLLOWS
1. if all the atoms are attached to chirality centre are diff , then the sequence of priority is decided by the atomic.no.
2. if 2 atoms hav da same same atomic no then the atm with highest atomic mass gets the 1^st priority
3.double bonds r treated as if they have 2 single bonds.
         it means that --C=O IS TAKEN AS --C--O
                                                                |
                                                               O
4.in case if the chiral atom is attached to same atoms ,then the priority is decided by the by comparing the other groups
5. after assigning the priority to the 4 atoms attached to the asymmetric carbon atom the molecule is drawn according to the FISCHER structure formula.

IF HELPFUL DO RATE ME

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