The photolysis of some α-iodo-nitroalkanes in solution

Abstract

α-Iodo-nitroalkanes decompose photochemically into α-nitroalkyl radicals and iodine. The α-nitroalkyl radical is detected by trapping with 2-methyl-2-nitrosopropane and identified by the hfs-constants of the resulting β-nitronitroxide observed with ESR. In the absence of nitroso compounds the α-nitroalkyl radicals can lose hydrogen to give nitro-olefins (70–80%). Minor products are nitroalkane (<5%) and ketone (10%), the latter via rearrangement of the α-nitroalkyl radical and loss of NO. When the HI elimination is blocked, as is the case with 2-iodo-2-nitroadamantane, the yield of ketone increases to 80%. Upon stabilization of the α-nitroalkyl radical by a phenyl group, dimerization becomes important. In the case of 1-cyclopropyl-1-iodo-1-nitroethane a considerable amount of ring opened product is isolated.