Question

Draw the product formed when each of the following compounds undergoes an electrocyclic reaction
a. under thermal conditions.
b. under photochemical conditions.

Short answer

a. Under thermal condition

b. Under photochemical condition

1.

2.

Step-by-step solution

Formation of 1st product under thermal condition

in each of molecule the system is same, that is coming 4 double bonds and 4 will be HOMO and antisymmetric. So the product will be trans product.

Formation of 2nd product under thermal condition

The molecule with alternating double bonds one is in the upper direction and the other one in same direction. So the product will be cis product.

Formation of 1st product under photochemical condition

Under photochemical condition here 5 is HOMO and it will symmetric and the dis-rotation will occurs here. So the product will be cis product.

Formation of 2nd product under photochemical condition

Under photochemical condition here 5 is HOMO and it will symmetric and the con-rotation will occurs here.So the product will be trans product.