Question

QUESTION 14 A biological molecule with three chirality centers is designated "SRS using the Cahn-ingold-Prelog labeling scheme. What label would its enantiomer have?

Answer 1

(i) The enantiomer of the "SRS" biological molecule should be designated "RSR"

(ii) Both the higher priority groups on each carbon (F, Cl) are present on the same side of the C=C plane. Hence, the given isomer is a Z-isomer.

The corresponding E-isomer will be the alkene in which both F and Cl are present on the opposite sides of the C=C plane, i.e. either you can reverse exchange H and F on the left-side carbon or you can exchange OH and Cl on the right-side carbon.