The Azide-Allene Dipolar Cycloaddition: Is DFT Able to Predict Site- and Regio-Selectivity?

Abstract

The site- and regio-selectivity of thermal, uncatalysed 1,3-dipolar cycloadditions between arylazides and mono- or tetra-substituted allenes with different electronic features have been investigated by both conceptual (reactivity indices) and computational (M08-HX, ωB97X-D, and B3LYP) DFT approaches. Both approaches show that these cycloadditions follow a nonpolar one-step mechanism. The experimental site- and regio-selectivity of arylazides towards methoxycarbonyl- and sulfonyl-allenes as well as tetramethyl- and tetrafluoro-allenes was calculated by DFT transition state calculations, achieving semiquantitative agreement to both previous and novel experimental findings. From the mechanistic standpoint, 1H-NMR evidence of a methylene-1,2,3-triazoline intermediate reinforces the reliability of the computational scheme.

Negligible Substituent Effect as Key to Synthetic Versatility: a Computational‐Experimental Study of Vinyl Ethers Addition to Nitrile Oxides

“…Concerted 1,3-dipolar cycloadditions are often studied with computational modeling. [5,7,[11][12][13][54][55][56][57][58] The cycloadditions to nitrile oxides of substituted alkenes and alkynes are no exception. [11,13,59,60] Most noticeable computational studies address regioselectivity of 1,3-dipolar cycloadditions.…”

“…Methods of quantum chemical modeling implemented in modern software packages have potentially high accuracy and require relatively small hardware resources and researcher‘s time [1–4] . Modeling is exceptionally efficient in deciphering reaction mechanisms [5–14] …”

“…Concerted 1,3‐dipolar cycloadditions are often studied with computational modeling [5,7,11–13,54–58] . The cycloadditions to nitrile oxides of substituted alkenes and alkynes are no exception [11,13,59,60] .…”

“…[1][2][3][4] Modeling is exceptionally efficient in deciphering reaction mechanisms. [5][6][7][8][9][10][11][12][13][14] Isoxazole ring is a key structural moiety of valuable pharmaceutical substances (Figure 1). [15] Among them are antibiotics, [16][17][18][19] as cloxacillin, [16,18,20] dicloxacillin [16,18,[20][21][22] and flucloxacillin, [16,18,20,23,24] which were included in the WHO Model List of Essential Medicines and recommended for the treatment of a wide range of bacterial infections.…”

Theoretical Analysis of OLED Performances of Some Aromatic Nitrogen-Containing Ligands

“…Density Functional Theory (DFT) that was revealed in accordance with this goal uses the electron density to identify the reactivity or stability [11][12][13][14][15][16][17]. It should be noted that hybrid functionals such as B3LYP and M062 are widely preferred in the studies regarding the explanation of reactivity properties of molecules [18][19][20][21][22][23][24]. Additionally, in the studies also researching organic light emitting diode performances of various molecules, the aforementioned functionals have been used [25][26][27][28][29][30][31].…”