Interplay between aromaticity and strain in double group transfer reactions to 1,2-benzyne

Abstract

Density Functional Theory calculations are used to explore the double hydrogen atom transfer from different alkanes to 1,2-benzyne. State-of-the-art calculations including the Activation Strain Model of reactivity, Energy Decomposition Analysis, and Valence Bond methods, reveal the origins of the relatively low activation barriers computed for these processes compared to the analogous reaction involving acetylene. In addition, the interplay between the in-plane aromaticity of the corresponding transition states and the variation of the π-aromaticity associated with the benzyne moiety as well as their influence on the barrier heights of the transformations are analyzed in detail.

Predicting and Understanding the Reactivity of Aza[60]fullerenes

“…2.5 Å) and becomes increasingly more stabilizing when reaching the corresponding transition state region. Similar behavior was found in related DA reactions , as well as in different types of pericyclic reactions . Nevertheless, the strong destabilizing effect of the deformation energy required to adopt the transition state geometry (Δ E strain ) overcomes the stabilization provided by the interaction term and therefore becomes the major factor controlling the activation barrier of the process.…”

A molecular electron density theory study of the [3 + 2] cycloaddition reaction of nitrones with strained allenes

“…2,5 Note that pseudoradicals are closed-shell species topologically characterised by the presence of at least one V(C) monosynaptic basin integrating less than 1.0e at one carbon atom. 6 Unlike arynes and cyclic alkynes, whose structure and reactivity have been widely studied, [1][2][3]7 highly strained allene species have been studied to a much lesser extent. Since 1966, when Wittig reported, for the rst time, the existence of 1,2-cyclohexadiene (CHDE) 10, 8 the chemistry of this highly strained species has received little attention especially compared to its aryne and alkyne counterparts.…”

Computational insights into the S3transfer reaction: A special case of double group transfer reaction featuring bicyclically delocalized aromatic transition state geometries

“…Note that the ACID method allows visualising the density of electrons that are not localized at an atom or bond but “mobile” within a molecule when it is subjected to a magnetic field . The synchronicity of the reactions was quantified by using approach of Moyano et al, based on the changes in the Wiberg bond indexes ( B i ) of the bonds formed and broken . The NBO 6.0 program package was used to obtain B i values, as well as to perform natural bond orbital analyses.…”