Which of the following compounds has a double bond that is conjugated with the π system of the benzene ring?
a. Allylbenzene
b. p-Benzyltoluene
c. 3-Phenylcyclohexene
d. 3-Phenyl-1,4-pentadiene
e. 2-Phenyl-1-decene
Can't find the solution
To determine which of the compounds has a double bond that is conjugated with the π system of the benzene ring, we need to examine each compound and identify if there is a carbon-carbon double bond that is directly connected to the benzene ring.
a. Allylbenzene does not have a double bond directly connected to the benzene ring.
b. p-Benzyltoluene does not have a double bond directly connected to the benzene ring.
c. 3-Phenylcyclohexene does not have a double bond directly connected to the benzene ring.
d. 3-Phenyl-1,4-pentadiene has a double bond that is directly connected to the benzene ring. This compound has a conjugated system.
e. 2-Phenyl-1-decene does not have a double bond directly connected to the benzene ring.
Therefore, the compound with a double bond that is conjugated with the π system of the benzene ring is d. 3-Phenyl-1,4-pentadiene.
To determine which of the compounds has a double bond that is conjugated with the π system of the benzene ring, we need to understand what "conjugation" means in organic chemistry.
Conjugation refers to the presence of alternating single and multiple bonds in a molecule. A conjugated system has overlapping p-orbitals along the chain of atoms, allowing the delocalization of electrons. In the case of a benzene ring, the delocalized π electrons are spread over all six carbon atoms, creating a stable aromatic system.
Now, let's analyze each compound to identify if their double bonds are conjugated with the π system of the benzene ring:
a. Allylbenzene:
In allylbenzene, there is a double bond between a carbon atom of the benzene ring and one of the neighboring carbon atoms. This double bond is not part of an extended π system, as it is not conjugated with the benzene ring.
b. p-Benzyltoluene:
In p-benzyltoluene, there is a methyl group (CH3) attached to one of the carbon atoms of the benzene ring. Again, the double bond is not part of a conjugated π system, as it is not directly connected to the benzene ring.
c. 3-Phenylcyclohexene:
In 3-phenylcyclohexene, there is a double bond between a carbon atom of the cyclohexene ring and a carbon atom that is part of the benzene ring. The double bond is conjugated with the π system of the benzene ring.
d. 3-Phenyl-1,4-pentadiene:
In 3-phenyl-1,4-pentadiene, there are multiple double bonds extending from the benzene ring. Since these double bonds are part of the π system of the benzene ring, they are conjugated.
e. 2-Phenyl-1-decene:
In 2-phenyl-1-decene, there is a double bond between two carbon atoms that are not connected to the benzene ring. Therefore, the double bond is not conjugated with the π system of the benzene ring.
Based on this analysis, the compound that has a double bond conjugated with the π system of the benzene ring is:
c. 3-Phenylcyclohexene
Here are structures for a,b,and c. Both d and e are simple enough for you to draw the structures yourself. I would focus my attention on e.
a. http://www.google.com/search?q=allylbenzene&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
b. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=117002
c. http://voh.chem.ucla.edu/vohtar/spring00/30H/pdf/hkey1.pdf
d.