Which of the following is not a correct designation for a sigmatropic rearrangement?

Question

Quizplus · Accepted Answer

Sigmatropic rearrangements are a type of pericyclic reaction where a sigma bond (a single covalent bond) adjacent to one or more π systems (conjugated system of electrons) shifts its position. The notation [m,n] describes the movement of the sigma bond and the π electrons involved in the rearrangement. The first number (m) indicates the position of the original sigma bond relative to the π system, and the second number (n) indicates the position where the sigma bond ends up. For a sigmatropic rearrangement to be valid, both m and n must be odd numbers or both must be even numbers, reflecting the conservation of orbital symmetry. Therefore, a [3,1] rearrangement, where one number is odd and the other is even, does not fit the criteria for sigmatropic rearrangements and is not a correct designation.

Which of the Following Is Not a Correct Designation for a Sigmatropic