Q.30-20

Question


Would you expect the following reaction to proceed in a conrotatory or
 disrotatory manner? Show the stereochemistry of the cyclobutene product, and explain your answer.



Step-by-Step Solution

Verified
Answer

The reaction happens through disrotatory mode which yields the fused cyclobutene with 2 hydrogen at the ring junction cis to each other.

1HOMO photochemical reaction


The two electron pairs in the electrocyclic reaction can be involved. The HOMO for photochemical reaction can be given below.



2Bonding is in disrotatory mode



It shows that the bonding is disrotatory mode. Thus, the reaction happens through disrotatory mode which yields the fused cyclobutene with 2 hydrogen at the ring junction cis to each other.


The reaction which involves the diene cyclization ring under photochemical reaction.