On the Number of π‐Electrons Involved in Stepwise Cycloaddition Reactions

Abstract

AbstractThe development of higher‐order cycloadditions has mainly been restricted by the requisite usage of highly conjugated and reactive π‐systems. Recent years have witnessed organocatalysis as a potent mediator for several of the challenges associated herein, rendering higher‐order cycloadditions a legitimate option for achieving the selective construction of specific molecular scaffolds. These developments reinvigorate the efforts to try to understand the underlying principles for cycloadditions involving a higher number of π‐electrons than the “classical” cycloadditions; how do we properly address the impact which the addition of further π‐electrons have on the reactivity of a system? Herein, computational investigations of two model higher‐order cycloaddition systems have been performed to try to provide insights on changes in energetic barriers induced by the presence of benzofusions in a position which is unobstructive to the reactivity. With experimental substantiation as support, these studies might open up for a discussion on whether the π‐electrons of benzofused systems simply act as spectator electrons, or play a tangible role on the observed reactivity to an extent where a distinct nomenclature is meritable.