Question

Question:Consider cycloheptatrienone and ethylene, and draw a possible product formed from each type of cycloaddition:

(a) [2 + 2]

(b) [4 + 2]

(c) [6 + 2]

Short answer

Answer

Step-by-step solution

Cycloaddition reaction

Cycloaddition reaction is a C-C bond-forming addition reaction between two compounds having pi-bonds. It is similar to an electrocyclic reaction and can occur under thermal or photochemical conditions.

A cycloaddition reaction can be [2+2], [4+2], or [6+2], depending on the types of bonds present in the reacting systems.

[2+2] Cycloaddition reaction

Cycloheptatrienone can undergo [2+2] addition with ethylene.The reaction is shown below:

[4+2] Cycloaddition reaction

The two pi-bonds of cycloheptatrienone can undergo [4+2] addition with ethylene.The reaction is shown below:

[6+2] Cycloaddition reaction

All the pi-bonds of cycloheptatrienone can undergo [6+2] addition with ethylene.The reaction is shown below: