Investigation into the Regiochemistry of 1,3‐Dipolar Cycloaddition of C,N‐Diphenyl Nitrone with Some Vinyl Sulfoximines as Dipolarophile: Theoretical Studies

Abstract

The regiochemistry of 1,3-dipolar cycloaddition reactions of C,N-diphenyl nitrone with some vinyl sulfoximines as dipolarophile was investigated using density functional theory (DFT)-based reactivity indexes and activation energy calculations at B3LYP/6-31G(d) level of theory. Analysis of the geometries and bond orders (BOs) at the TS structures associated with the different reaction pathways shows that these 1,3-dipolar cycloaddition reactions occur via an asynchronous concerted mechanism. Analysis of the local electrophilicity and nucleophilicity indexes permits an interpretation about the regioselectivity of these 1,3-dipolar cycloaddition reactions. The theoretical results obtained in the work clearly predict the regiochemistry of the isolated cycloadducts and agree to experimental outcomes.

Mechanism and Regioselectivity of the 1,3-Dipolar Cycloaddition of Methyleneamine N-Oxide with Cyclopent-3-Ene-1,2-Dione and its Aza, Oxa and Thia Analogues: A Dft Approach

“…1,3-Dipolar cycloaddition (1,3-DC) of unsaturation (ene) to a nitrone is a powerful tool for the synthesis of five-membered heterocycles containing an isoxazole structure [3 -6]. The 1,3-DC reaction is a pericyclic reaction [7] in which 1,3-dipoles and dipolarophiles combine to generate five-membered rings [8]. For the first time in 1960, Huisgen et al [9,10] introduced the concept of 1,3-DC reactions.…”

Theoretical analysis of the mechanism and regioselectivity of the 1, 3-dipolar cycloaddition of E-3-(dimethylamino)-1-(10H-phenothiazin-2-yl)prop-2-en-1-one with some nitrilimines using DFT and the distortion/interaction model

“…8 Experimentally; it has been found that the cycloaddition reactions of nitrilimines 1a-c with E-3-(dimethylamino)-1-(10H-phenothiazin-2-yl) prop-2-en-1-one 2 give preferentially the cycloadducts 3a, 3b and 3c respectively, shown in Scheme 1. 9 In continuation of our studies on the mechanism and regioselectivity of the1,3-DC reactions, [10][11][12][13][14][15][16][17][18] we became interested in the above mentioned reactions based on activation energy calculations, the distortion/interaction model and DFT-based reactivity indexes.…”