McMurry (Kap. 7,4) - Alkene stereochemistry, E-Z designation

Question 1

What are the rules for the E-Z configuration?

Answer 1

(firstly you have to have a tri or tetra substituted C=C)

1) Look at the two attached substituents on each C and rank them from atomic number - the one with higher atomic number gets the higher rank, and one with lower gets lower rank.

2) If desicion cant be reached from the first atom of the substituents, look at the second, third, fourth etc.. (until a difference is found).

3) Multiple bonds atoms are equivilant to the same number of single bonded atoms.

For examples, look at page 189.