Abstract
Oxidative free-radical cyclizations of unsaturated 2-cyclohexenones 9a, 9b, 17, and 24 with Mn(OAc)3 afford unsaturated α′-keto radicals such as 10 that cyclize to afford bicyclic products. The major process with 2-cyclohexenone 27 is conjugate addition of acetate to form β-acetoxy α-keto radical 37. Unsaturated aldehydes 45, 57a, and 57b are oxidized to radicals that cyclize to give cyclopentane- and cyclohexanecarboxaldehdyes.