Unveiling the Different Reactivity of Bent and Linear Three-Atom-Components Participating in [3 + 2] Cycloaddition Reactions

The reactivity of a series pairs bent and linear three-atom-component (B-TACs L-TACs) participating in [3 + 2] cycloaddition (32CA) reactions towards ethylene electrophilic dicyanoethylene (DCE) have been studied within the Molecular Electron Density Theory. While pseudodiradical structure B-TACs changes to that pseudoradical or carbenoid L-TACs upon dehydrogenation, zwitterionic remain unchanged. Conceptual Functional Theory (CDFT) indices characterize five nine TACs as strong nucleophiles polar ethylenes. activation energies 32CA with DCE range from 0.5 22.0 kcal·mol?1, being between 4.3 9.1 kcal·mol?1 lower than those ethylene. In general, are more reactive their L-TAC counterparts. A change regioselectivity is found these reactions; while meta regioselective, ortho regioselective. geometrical parameters transition state structures suggest formation single bond involving most carbon advanced. asynchronicity also found.