We learned about E and Z structures but im confused :S
i have a question that involves a benzene ring and a cyclohexane ring on the same side of a double bond but i don't know which one has more prority over the other...can someone plz help?
thx
When it comes to determining priority in E and Z structures, the priority is assigned based on the Cahn-Ingold-Prelog (CIP) rules. These rules are used to assign priority to substituents on a molecule based on the atomic numbers of the atoms directly bonded to the carbon.
In your case, you have a benzene ring and a cyclohexane ring on the same side of a double bond. To determine which one has higher priority, you need to compare the substituents on each ring based on the CIP rules.
First, assign a priority to each atom attached to the double bond. Look at the atoms directly bonded to the carbon atoms of the double bond, prioritize them based on their atomic numbers. For example, if you have an oxygen atom (higher atomic number) on one side of the double bond and a carbon (lower atomic number) on the other side, the oxygen atom would have higher priority.
Once you've assigned priority to the atoms, compare the substituents on each ring. If there are multiple substituents on each ring, compare the atoms attached to each substituent based on the rules above.
If there is still a tie, you move outward from the double bond until you find points of difference to break the tie. For example, if two substituents are identical, you continue moving along the ring until you find a point of difference.
Ultimately, the ring that has the substituent with the highest priority will take precedence and determine whether the molecule is E (trans) or Z (cis).
It's important to note that assigning priorities based on the CIP rules can be a bit complex, especially when dealing with larger molecules. In such cases, it may be helpful to consult with a teacher or refer to specific examples and practice problems to gain more familiarity with the process.