Arsabenzene (IUPAC name: arsinine) is an organoarsenic heterocyclic compound with the chemical formula C5H5As.

It belongs to a group of compounds called heteroarenes that have the general formula C5H5E (E= N, P, As, Sb, Bi).

[1] The organotin compound undergoes As/Sn exchange with arsenic trichloride to give 1-chloroacyclohexadiene, which loses a HCl upon heating, forming the arsabenzene.

[1] Arsabenzene undergoes electrophilic aromatic substitution at its ortho and para positions.

Thus the ability of these heterobenzenes to undergo the Diels Alder reaction with this electrophile increases down the periodic table.