Chapter C, Problem C.25P

Interpretation Introduction

(a)

Interpretation:

The E or Z configuration for the given double bond is to be determined.

Concept introduction:

When assigning priorities to substituents, the atom having the greater atomic number has a higher priority. In the case of comparison between isotopes, the one having the greater atomic mass gets the higher priority. If the substituents are attached by the same atom, then the set of atoms one bond away from the point of attachment is compared. In each set, the highest priority atoms are compared. If the sets of atoms one bond away from the point of attachment are identical, then the sets of atoms one additional bond away from the point of attachment are compared. If the higher priority groups attached to the double bonded carbon atoms are on the same side of the double bond, the alkene is assigned Z configuration. If the higher priority groups attached to the double bonded carbon atoms are on the opposite side of the double bond, the alkene is assigned E configuration. When more than one double bond is present, each is assigned E or Z configuration, and the location of each double bond appears immediately before the E or Z designation.

Interpretation Introduction

(b)

Interpretation:

The E or Z configuration for the given double bond is to be determined.

Concept introduction:

When assigning priorities to substituents, the atom having the greater atomic number has a higher priority. In the case of comparison between isotopes, the one having the greater atomic mass gets the higher priority. If the substituents are attached by the same atom, then the set of atoms one bond away from the point of attachment is compared. In each set, the highest priority atoms are compared. If the sets of atoms one bond away from the point of attachment are identical, then the sets of atoms one additional bond away from the point of attachment are compared. If the higher priority groups attached to the double bonded carbon atoms are on the same side of the double bond, the alkene is assigned Z configuration. If the higher priority groups attached to the double bonded carbon atoms are on the opposite side of the double bond, the alkene is assigned E configuration. When more than one double bond is present, each is assigned E or Z configuration, and the location of each double bond appears immediately before the E or Z designation.