Understanding the local reactivity in polar organic reactions through electrophilic and nucleophilic Parr functions

Abstract

Building upon our recent studies devoted to the bonding changes in polar reactions [RSC Advances, 2012, 2, 1334 and Org. Biomol. Chem., 2012, we propose herein two new electrophilic, P þ k , and nucleophilic, P { k , Parr functions based on the spin density distribution at the radical anion and at the radical cation of a neutral molecule. These local functions allow for the characterisation of the most electrophilic and nucleophilic centres of molecules, and for the establishment of the regio-and chemoselectivity in polar reactions. The proposed Parr functions are compared with both, the Parr-Yang Fukui functions [

A Molecular Electron Density Theory Study of the Reactivity of Azomethine Imine in [3+2] Cycloaddition Reactions

“…Recently, Domingo proposed the nucleophilic and electrophilic Parr functions [28], derived from the changes of spin electron-density reached via the GEDT process from the nucleophile to the electrophile, as a powerful tool in the study of the local reactivity in polar or ionic processes.…”

<strong>A THEORETICAL ANALISYS OF THE REACTIVITY OF ACYL AZAHETEROCYCLES AS DIENOPHILES IN CYCLOADDITION REACTIONS </strong>

“…It is classified as a moderate electrophile [16]. On the other hand, 1-trimethylsilyloxy-1,3-butadiene (3.67 eV) and Danishefsky's diene (3.77 eV) are on the borderline of strong nucleophiles [17].…”

An experimental and quantumchemical study of [2+3] cycloaddition between (Z)-C-(m,m,p-trimethoxyphenyl)-N-(p-methyphenyl)-nitrone and (E)-3,3,3-trichloro-1-nitroprop-1-ene: mechanistic aspects

“…In particular, we decided: (i) to analyse the nature of addent interactions with respect to the theory, developed intensively in recent years [14][15][16][17][18] , of electrophilicity and nucleophilicity indexes, (ii) identify reaction stereochemistry, (iii) perform kinetic studies (determination of activation parameters and the kinetic solvent effect), and (iv) perform quantumchemical simulations of actual reaction pathways. Such a comprehensive approach should in our opinion give a clear view of the course of the reaction in question and make a large contribution to our knowledge of the mechanistic aspects of nitrone [2+3] cycloaddition.…”

“…The electrophilicity difference () for the reagent pair is more than 1.7 eV. Therefore the reaction is considered strongly polar 18 . The regioselectivity of such reactions may be forecast using local electrophilicity k and nucleophilicity Nk indexes, which were calculated in terms of global reactivity indexes and appropriate Paar functions 18 .…”

“…Therefore the reaction is considered strongly polar 18 . The regioselectivity of such reactions may be forecast using local electrophilicity k and nucleophilicity Nk indexes, which were calculated in terms of global reactivity indexes and appropriate Paar functions 18 . As can be seen from Table 1, the  carbon atom of the nitrovinyl moiety is the most strongly electrophilic reaction centre in the nitroalkene (k=0.75 eV).…”