What is an electrocyclic reaction?
Q: What is an electrocyclic reaction?
A: An electrocyclic reaction is a type of organic chemical reaction in which a conjugated double bond system opens or closes to form a ring.
Q: What is the difference between conrotatory and disrotatory modes?
A: In a conrotatory mode, the substituents located at the ends of a conjugated double bond system move in the same (clockwise or counterclockwise) direction during ring opening or ring closure. In contrast, in a disrotatory mode, they move in opposite directions.
Q: How does orbital symmetry affect these reactions?
A: The orbital mechanics of the reaction needs to be taken into account when determining whether it follows conrotatory or disrotatory rules. For example, systems containing 4n + 2 pi electron are stereospecific and follow the conrotatory rule due to preservation of orbital symmetry in their highest occupied molecular orbitals (HOMO). Systems containing 4n pi electrons show the opposite disrotatory mode. This is also true for rearrangements of 4n + 2 pi (where n is a whole number) electrons driven by light (photoinduced). Photoinduced rearrangements of 4n pi electron systems (where the number of electrons is divisible by 4) follow the disrotatory rule.
Q: What are Woodward–Hoffmann rules?
A: The Woodward–Hoffmann rules summarize different types of electrocyclic reactions and how they are affected by factors such as orbital symmetry and presence/absence of light energy.
Q: What does this picture show?
A: The picture shows an example conversion from trans-cis-trans-2,4,6-octatriene to cis-dimethylcyclohexadiene and illustrates how substituents move differently depending on whether it follows conorotary or disrorotary modes - clockwise vs counterclockwise respectively when viewed from above.
