Abstract: The regioselectvity and the mechanism of the (32CA) cycloadditions reactions of 1-bromo4-vinylbenzene 1 and 1-chloro-4-vinylbenzene 2 with benzonitrile oxide 3 were investigated under
the molecular electron density theory (MEDT) at the B3LYP/6-311++G(d,p) computational level.
Evaluation of the ELF reveals that these zwitterionic type (zw-type) 32CA reactions take place in a
two-stage one-step mechanism. This MEDT study shows that the meta isoxazolines are kinetically and
thermodynamically favored over the ortho ones, these 32CA reactions being completely regioselective,
in agreement with experimental outcomes. In addition, the efficiency of isoxazolines against SARSCoV-2 have been also investigated. According to the docking analysis, the present study concludes
that 5-(p-bromophenyl)-3-phenyl-2-isoxazoline (B-m) shows better interactions for the inhibition of
SARS-CoV-2 in comparison to chloroquine.