[eric123]

Hello...A couple of weeks ago, i had a homework, wherein it was asked as to why is dewar benzene so stable at room temperature???....the answer that i found was that the dewar benzene if underwent an electrocyclic reaction, it would lead to the formation of benzen with a trans double bond which is actually thermodynamically unfavourable....
this is exactly the point i dont understand...why is a trans double bond in rings less than 8-membered rings so unstable or unfavourable?...I would be thankful if anyone can help me out with a good explanation....thanks...

[Dan]

Try to make a model of trans-cyclohexene, the reason for its instability will quickly become clear.