In which of the following systems will an antarafacial shift be impossible?
E) None of these systems can undergo an antarafacial shift.

Question

In which of the following systems will an antarafacial shift be impossible? 
E) None of these systems can undergo an antarafacial shift.

Quizplus · Accepted Answer

The key factor for determining the possibility of an antarafacial shift is the relative orientation of the orbitals involved in the reaction. In option A, the substituent is located on the same side of the double bond as the migrating group. Therefore, an antarafacial shift would require the migrating group to cross through the pi bond, which is not possible. On the other hand, in all other options (B, C, D), the substituent is located on the opposite side of the double bond as the migrating group, which allows for an antarafacial shift to occur.

In Which of the Following Systems Will an Antarafacial Shift