Chlorination of conjugated nitroalkenes with iodobenzene dichloride or sulfuryl chloride
to give target α-chloronitroalkenes in good yields is described. Details of the procedure
depend on the donating ability of the nitroalkene substituents. The activity of the
described chlorinating agents increases in order ‘PhICl2/Py’ < ‘SO2Cl2’ < ‘SO2Cl2/HCl’ with the former producing the best yields for highly donating substrates and
the latter for non-activated groups. An autocatalytic role of hydrogen chloride and
the chemoselectivity of chlorination were also demonstrated.
Key words
nitroalkenes - halogenation - chlorination - nitro compounds - chemoselectivity