Question

Which of the following reactions is more likely to occur? Explain.

Short answer

To identify which among the two reactions is more likely to occur can be stated.

Step-by-step solution

Statement for the first reaction

The involvement of reaction 1 has reverse (4+2) cycloaddition. There is an involvement for three electron pairs. There is an involvement of molecular orbitals arranged in such a way that the reaction will states with suprafacial geometry under thermal conditions.

Statement for the second reaction

The involvement of reaction 2 has a reverse (2+2) cycloaddition reaction. There is an even electron pair number involved. The thermal reaction will require an antarafacial geometry. There is no possibility in the arrangement for reactant molecular orbitals. This reverse addition reaction will have no possibility to occur.