Understanding the kinetics and molecular mechanism of the Curtius rearrangement of 3-oxocyclobutane-1-carbonyl azide

Are There Only Fold Catastrophes in the Diels–Alder Reaction Between Ethylene and 1,3-Butadiene?

“…24 It should be strongly emphasized however that such correlation between ELF and chemical bonding is of course just topological, and not energetical. BET has provided meaningful insights on an everincreasing number of reactive processes related to problems in almost all fields of chemistry, 24c, 24d including, for instance, key questions on bonding and reactivity related to the activation of C-H bonds, 25 proton/hydrogen transfer reactions, 26 [4+2] cycloadditions, 9,27 [3+2] cycloadditions, 28 [1,3] dipolar cycloadditions, 9,29 the process of fixation of CO2 by metal complexes, 30 decarbonylation of unsaturated cyclic ketones, 31 the nature of phase transitions for the group IV elements, 32 the formation of hemiaminals, 33 Cope, 9,34 and Claisen 35 rearrangements, the thermal decomposition of -ketoesters, 36 hydrometallation of acetylene, 37 oxidative additions of ammonia to pincer complexes, 38 the Curtis rearrangement, 39 the catalytic Noyori hydrogenation, 40 and the Wittig reaction. 5a In such a context, the suitability of the characterization of the local character of the local ELF function dependents on a proper identification of the associated elementary catastrophes, and hence, the analysis of how the equilibria of ELF change as the control parameters changes.…”

“…Moreover, a description of changes of the topologically defined molecular structures as a response to the variation of control parameters can be addressed via the theory of elementary catastrophes. , It has been mainly exploited within both the QTAIM and ELF ,, frameworks. Within the so-called bonding evolution theory (BET) framework, the transformation of the topology of the ELF along a chosen reaction path (e.g., the intrinsic reaction coordinate (IRC) , ) are characterized in terms of Thom’s elementary catastrophes. ,,, The BET has a demonstrated capability for studying the evolution of the rearrangement of electron pairing (as measured by the ELF) along the reactive path, and hence, chemically significant events, including bond making/breaking processes, become naturally associated with specific structural stability domains (SSDs) separated by catastrophe bifurcations. ,,, BET has provided meaningful insights on an ever-increasing number of reactive processes related to problems in almost all fields of chemistry, , including, for instance, key questions on bonding and reactivity related to the activation of C–H bonds, proton/hydrogen transfer reactions, [4 + 2] cycloadditions, , [3 + 2] cycloadditions, , [1,3] dipolar cycloadditions, ,, the process of fixation of CO 2 by metal complexes, decarbonylation of unsaturated cyclic ketones, the nature of phase transitions for the group IV elements, the formation of hemiaminals, , Cope , and Claisen − rearrangements, the thermal decomposition of α-ketoesters, hydrometalation of acetylene, oxidative additions of ammonia to pincer complexes, the Curtis rearrangement, the catalytic Noyori hydrogenation, and the Wittig reaction . We stress that any chemical reaction can, in principle, be in such a way represented in terms of a precise sequence of catastrophic bifurcations associated with electron pairing topologies that enable a straightforward rationalization or interpretation of the evolution of the key chemical concept of bonding patterns. ,,, …”

Unraveling the kinetics and molecular mechanism of gas phase pyrolysis of cubane to [8]annulene

“…18 The computational procedure in the CBS-QB3 method has been described elsewhere. 19,20 All quantum chemical calculations were carried out with the Gaussian 16 suite of programs. 21 The pressure-and temperature-dependent rate constants as well as thermodynamical parameters have been evaluated using the Kinetic and Statistical Thermodynamical Package (KiSThelP, Rev.…”

Do one‐step mechanisms always involve simultaneous evolution of electron density? QTAIM/IQA analysis of the Curtius rearrangement

“…Recently, the molecular mechanism of the Curtius rearrangement of 3‐oxocyclobutane‐1‐carbonyl azide has been described by using electron localization function (ELF) topological analysis . The authors concluded that the mechanism of the reaction is concerted but asynchronous.…”