My question is why is benzene less reactive than 1,3,5-cyclohexatriene? I cannot find anything on 1,3,5 cyclohexatriene and why it is more reactive.

I know that benzene does not undergo addition reactions and is extremely stable to oxidizing reagents. C atoms in benzene are connected by delocalized double bonds which make them available to all carbon atoms at the same time. This makes the ring system unusually stable.

I think your answer is fine. I was not able to find much information about 1,3,5-cyclohexatriene either but I did confer with a colleague who is an organic chemist. He tells me that in order for benzene to undergo those reactions that the resonance structure must be destroyed and that takes so much energy that it makes benzene much less reactive. In other words, the resonance present in benzene is what makes it more stable and that accounts for the less reactivity.

To understand why benzene is less reactive than 1,3,5-cyclohexatriene, we need to compare their structures and bonding characteristics.

Benzene, as you mentioned, consists of a hexagonal ring of carbon atoms connected by alternating single and double bonds. These alternating bonds create a resonance structure in which the pi electrons are delocalized throughout the entire ring. This delocalization of electrons gives benzene its remarkable stability and makes it less reactive. The stability arises from the fact that the delocalized pi electrons are spread out over the entire ring, resulting in a lower energy state.

On the other hand, 1,3,5-cyclohexatriene lacks the alternating single and double bonds found in benzene. It is an open-chain hydrocarbon with three isolated double bonds. Without the delocalization of electrons, 1,3,5-cyclohexatriene has higher reactivity compared to benzene.

The reactivity difference between benzene and 1,3,5-cyclohexatriene can be observed in many reactions. For example, benzene does not readily undergo addition reactions, while 1,3,5-cyclohexatriene is more susceptible to electrophilic addition reactions. The stability derived from the delocalization of pi electrons in benzene makes it harder for other molecules to attack and react with benzene's carbon-carbon double bonds.

In summary, the delocalization of pi electrons in benzene due to its alternating single and double bonds gives it exceptional stability compared to 1,3,5-cyclohexatriene, leading to less reactivity in benzene.