What is the configuration (E or Z) of the following alkene? (The numbers and letters are for reference in the solution.)

Question

Accepted Answer

At carbon-2, the methyl group has higher priority, by rule 1a. At carbon-3, rules 1a and 1b allow no decision, because the level-1 atoms (a1 and b1) are identical—both are carbons. Proceeding to step 2, the set of atoms (level-2 set) attached to either carbon a1 or b1 is (C,H,H); again, no decision is possible. According to step 3, we must now consider the atom of highest priority (carbon) in each level-2 set; these atoms are labeled a2 and b2, respectively. The level-3 set of atoms attached to a2 is (C,H,H); the level-3 set attached to b2 is (C,C,H). Notice that carbons a1 and b1 considered in the previous step are not considered as members of these sets, because we always work outward, away from the double bond, by step 2. The difference in the second atoms of each set—C versus H—dictates a decision. Because the level-3 set of atoms at carbon b2 has higher priority, the group containing carbon b2 (the isobutyl group) also has the higher priority. The process used can be summarized as follows:

Notice that, although Br has a higher priority than H, the decision point occurs before we reach the Br (which is in a level-4 set). Therefore, the Br-versus-H comparison is irrelevant in this case.

Because the groups of like priority are on the same side of the double bond, this alkene has the Z configuration; the name is (Z)-6,6-dibromo-3-isobutyl-2-heptene.

Question 4.6: What is the configuration (E or Z) of the following alkene? ...

Related Answered Questions

Give the IUPAC name of the following compounds, including the (E,Z) designation for the ...

Verified Answer:

Give the structure of an alkene that would give 2-bromopentane as the major (or sole) product of HBr addition. (The numbers are for reference in the solution.) ...

Verified Answer:

What is the configuration of the following stereoisomer of 3-methyl-2-pentene? (The numbers are for reference in the solution.) ...

Verified Answer:

Calculate the standard enthalpy difference between the cis and trans isomers of 2-butene. Specify which stereoisomer is more stable. The heats of formation are, for the cis isomer, 27.40 kJ mol–1, and for the trans isomer, 211.6 kJ mol–1 (21.77 and 22.72 kcal mol–1, respectively). ...

Verified Answer:

Name the following compound: ...

Verified Answer:

Draw a conventional structure corresponding to the following skeletal structure, and then name it. ...

Verified Answer:

Name the following compound using IUPAC substitutive nomenclature. ...

Verified Answer:

Tell whether each of the following molecules has a double-bond stereoisomer. If so, identify its stereocenters. ...

Verified Answer: