OXIDATIVE ADDITION-REACTIONS OF OMEGA-ALKENYL NITRONATE ANIONS

Anions are oxidatively added to nitronate anions to yield alpha-substi tuted nitroalkanes when potassium hexacyanoferrate(III) is used as oxi dant. Oxidation of nitronate anions yields intermediate alpha-nitroalk yl radicals, which undergo addition by anions to give intermediate alp ha-substituted nitroalkane radical anions, which are further oxidised to yield the alpha-substituted nitroalkanes. The nitronate anions used are derived from 5-nitrohex-1-ene, 6-nitrohept-1-ene, ndo-5-nitro-exo -6-phenylbicyclo[2.2.1]-hept-2-ene, and bicyclo[2.2.1]hept-5-en-endo-2 -yl)-2-nitropropane. The intermediate alpha-nitroalkyl radicals underw ent addition of anions to form radical anions faster than intramolecul ar cyclisation onto the omega-alkenes. The alpha-nitroalkyl radical de rived from 1-(bicyclo[2.2.1] hept-5-en-endo-2-yl)-2-nitropropane under went cyclisation when the oxidation was carried out in the absence of an added anion. The addition of anions (thiocyanate, benzenesulfinate, 4-chlorobenzenethiolate, and nitrite) to the alpha-nitroalkyl radical s derived from endo-5-nitro-exo-6-phenylbicyclo[2.2.1]hept-2-ene occur red stereoselectively from the less hindered exo face. Oxidative addit ion of 4-chlorobenzene-thiolate to the nitronate from endo-5-nitro-exo -6-phenylbicyclo[2.2.1]hept-2-ene gave an unusual cyclisation via addi tion of a thiyl radical to the alkene.