The usefulness of various quantum chemical algorithms (semiempirical, HF, DFT) for predicting the energy and geometry of transition states of polar pseudocyclic processes was analyzed using the example of a model cycloaddition process between (Z)-C,N-diphenylnitrone and (E)-2-phenyl-1-nitroethene. These studies clearly recommend the ωB97XD functional in 6-311+G(d) basis set as the relatively most precise tool for studying the mechanisms of polar pseudocyclic processes.

The correlation between coefficients from Dimroth equations and descriptors of global electron density transfer was explored based on the data available in the recent literature. We established that the obtained results should be very usable for the interpretation of the organic reactivity and molecular mechanisms.

Nitrones are an interesting group of organic compounds due to their spin-trapping properties. These chemical compounds are also useful building blocks via cycloaddition reactions. In this work, a comprehensive study about correlation of selected parameters come from quantum chemical and experimental studies, namely 1H chemical shifts, IR absorption bands and UV-Vis maximum absorptions as well as reactivity descriptors such as global electrophilicity and nucleophilicity with substituent constants of Hammett, Taft, Brown and Okamoto's as well as Exner for para substituent analogues of (Z)-C-phenyl-N-methylnitrones have been study. Based on presented results it should be noted that tested models of substituent constants correlate in a satisfactory way with computational data. The opposite conclusion is observed for spectral data derived from analysis performed for synthesized nitrones. The obtained results constitute a useful element for future research on reaction mechanisms involving the tested nitrones.

The nitrovinyl moiety is surely one of the most reactive fragments in organic chemistry, continuously employed to explore original pathways and reach new targets. One of the most important classes of chemicals containing this fragment are nitro-functionalised analogues of 1,3-butadiene. In this paper a comprehensive review study of these compounds is performed. The manuscript includes an analysis of physicochemical properties, spectral characteristic, synthesis, biological activity, and possible transformations of nitro substituted analogues of 1,3-butadiene. The analysis was divided into several parts, depending on the number of nitro groups included in the structure of a 1,3-butadiene analogue. In addition, the work includes information about hazards and safety principles when working with nitro compounds. Based on the analysis of the literature, it can be concluded that nitro-functionalised analogues of 1,3-butadiene exhibit diversified profile of properties, and an outstanding potential as valuable reagents in organic synthesis useful to obtain heterocycles that can be applied in medicine.

The regioselectivity of the [3+2] cycloaddition reactions between trans-β-nitrostyrene and C,N-diarylnitryle imine analogues as three atom components (TACs) has been studied with the use of Conceptual Density Functional Theory in the framework of Molecular Electron density Theory. Global and local reactivity indices were determined. Presented quantum-chemical computations showed that, for the reaction of nitroalkene with diphenylnitryle imine, the most favourable reaction path is determined by the nucleophilic attack of C3 carbon atom of TAC on an electrophilic C_α carbon atom of nitroalkene. Therefore, the creation of 1,3,4-triphenyl-5-nitro-Δ²-pyrazoline, according to channel B, is more probable. Similarly, to presented conclusion, for reactions of nitroalkene with nitryle imines containing ED group at para position of the phenyl ring also the most favourable reaction paths run through channel B leading to 1,3,4-triphenyl-5-nitro-Δ²-pyrazolines. In turn, reactions of nitroalkene with nitryle imines containing EW group at para position of the phenyl ring have the opposite preference and the most favourable reaction paths is channel A leading to 1,3,5-triphenyl-4-nitro-Δ²-pyrazolines.

The regioselectivity of the [3+2] cycloaddition reactions between benzonitrile N-oxide as three-atom component and two series of para-substituted β-nitrostyrene analogues was analysed in the framework of
a Molecular Electron Density Theory. All of the considered processes were found to be initiated by the attack of the most nucleophilic oxygen atom in the benzonitrile N-oxide on the most electrophilic carbon atom (C_α) in the nitroalkenes. This type of interaction favours the formation of 4-nitro-substituted
Δ²-isoxazolines.

In this review we present recent progress in the cycloaddition reactions of conjugated nitroalkenes with alkenes, conjugated 1,3-dienes or three atoms components (eg. nitrones, azides, diazocompounds, azomethine imines and ylides).

A molecular mechanism of the [3+2] cycloaddition has been explored using various DFT theoretical levels. It was found that the reaction proceeds via transition states with different synchronicity, but no intervention of the theoretical possible zwitterionic intermediates. Additionally, regioselectivity of the cycloaddition process has been analysed using vibrational analysis of localised TSs