A DFT computational study of the molecular mechanism of [3 + 2] cycloaddition reactions between nitroethene and benzonitrile N-oxides

Abstract

DFT calculations were performed to shed light on the molecular mechanism of [3 + 2] cycloadditions of simple conjugated nitroalkenes to benzonitrile N-oxides. In particular, it was found that these processes proceed by a one-step mechanism through asynchronous transition states. According to the latest terminology, they should be considered polar but not stepwise processes.

Competition between [2 + 1]- and [4 + 1]-cycloaddition mechanisms in reactions of conjugated nitroalkenes with dichlorocarbene in the light of a DFT computational study

“…The most universal methodology for preparing nitrofunctionalized cyclic compounds is cycloaddition reactions involving respective conjugated nitroalkenes (CNA) [4,11]. In this way, several four- [12,13], five - [14][15][16][17], and six-membered [18][19][20][21] nitro-cycles have been prepared. This is possible via [2 + 2], [3 + 2], and [4 + 2] cycloadditions, respectively.…”

“…On the other hand, five nitroalkenes (1ae) characterized by a different type of substitution were selected. All these nitrocompounds may be prepared with good yields [26], can exist as relatively stable compounds, and have been recently tested as components of other type cycloadditions (nitroethene 1a [14,16,27], 2-niroprop-1ene 1b [28], 1-chloro-1-nitroethene 1c [14,18,29], E-1nitroprop-1-ene 1d [28,30,31], E-2-chloro-1-nitroethene [31]). We hope that this study will help to further understand the nature of the title reactions and will be useful in organic synthesis.…”

Understanding the mechanism of the decomposition reaction of nitroethyl benzoate through the Molecular Electron Density Theory

“…They are useful compounds applied, e.g. in syntheses of many four-, fiveand six-membered compounds in cycloaddition reactions [6][7][8][9][10][11]. Applications of nitroalkenes in organic synthesis are largely due to their ease of conversion into a variety of functionalities.…”

Microwave‐Assisted Solvent‐Free Synthesis of Ipsapirone

“…It was determined that the potentially attractive way for ipsapirone 5 synthesis using 8‐(pyrimidin‐2‐yl)‐5,8‐diazaspiro[4.5]decan‐5‐ium bromide 6 is not achievable in the tested conditions. This phenomenon can be explained by the molecular electron density theory , which in recent years has been successfully used to explain the reactivity of components in numerous different types of bimolecular reactions . The global nucleophilicity descriptors needed for this purpose ( N ) were obtained by calculating B3LYP/6‐31G (d), using the equation proposed by Domingo : …”