A molecular electron density theory investigation of the molecular mechanism, regioselectivity, stereoselectivity and chemoselectivity of cycloaddition reaction between acetonitrile N-oxide and 2,5-dimethyl-2H-[1,2,3]diazarsole

The cycloaddition reactions (32CA) of acetonitrile N-oxide and 2,5-dimethyl-2H-[1,2,3]diazarsole 1 have been examined employing the molecular electron density theory through DFT calculations at the B3LYP/6-31G ++(d,p) computational level. Investigation of the relative energies related to the competitive ortho and meta reaction paths demonstrates a high chemo-, stereo- and regioselectivity for this 32CA reaction in clear conformity with the experimental results. The topological study of the electron localisation function of the certain points of the IRC associated with the construction of the As–C and C–O single bonds shows a zwitterionic-type structure. The 32CA reaction takes place via a two-stage one-step mechanism initialised with the formation of the As–C single bond.