The Effect of Position Replacement of Functional Groups on the Stepwise character of 1,3‐Dipolar Reaction of a Nitrile Oxide and an Alkene

It is a well‐known fact that by changing the 1,3‐dipolar cycloaddition (1,3‐ DC ) reaction mechanism from concerted to stepwise, the stereospecificity is lost; since in synthesizing the required heterocyclic molecules that reaction is a requisite, it is important to study the concertedness of that reaction. Several papers on this subject have already stated that the existence of electron withdrawing groups ( EWG ) or electron donor groups ( EDG ) on dipole or dipolarophile leads to a high‐energy differentiation between the dipole HOMO and dipolarophile LUMO (or vice versa ) as well as the emergence of an intermediate in the reaction pathway. This paper seeks answering the question of when an EWG on dipole and an EDG on dipolarophile could be a factor in making the reaction mechanism stepwise, and does repositioning of functional groups in replacing dipole and dipolarophile switches the reaction mechanism from stepwise into concerted or vice versa ?