An investigation of the molecular mechanism, chemoselectivity and regioselectivity of cycloaddition reaction between acetonitrile N-Oxide and 2,5-dimethyl-2H-[1,2,3]diazaphosphole: a MEDT study

Abstract

Abstract: The [3+2] cycloaddition (32CA) reactions of acetonitrile N-oxide with 2,5-dimethyl-2H-[1,2,3]diazaphosphole has been studied using the Molecular Electron Density Theory (MEDT) through DFT calculations at the B3LYP/6-31G(d,p) computational level. Analysis of the relative free energies associated with the competitive ortho and meta reaction paths shows high chemo- and regioselectivity for this 32CA reaction in clear agreement with the experimental outcomes. The topological analysis of the electron localization function (ELF) of the selected points of the IRC associated with the formation of the P-C and C-O single bonds indicates a zwitterionic type structure. The 32CA reaction takes place through a two-stage one-step mechanism initialized with the formation of the P-C single bond. Graphic abstract: The mechanism, the chemo-, and regioselectivity of the [3+2] cycloaddition (32CA) reaction between ethylnitrile oxide and 2,5-dimethyl-2H-[1,2,3]diazaphosphole, have been theoretically studied at the DFT/ B3LYP/6-31(d,p) computational level. DFT calculations account for the total chemo- and regioselectivity in total conformity with the experimental results.[Figure not available: see fulltext.].