Intramolecular hydrogen abstraction. (Diacetoxyiodo)benzene, a useful reagent for the remote functionalization of non-activated carbon atoms

Abstract

In previous papers we have reported that the system (diacetoxyiodo)benzene and iodine is more efficient and convenient to generate alkoxyl radicals from alcohols than those constituted from heavy metal derivatives (e.g. Pb(IV), Hg (II) and Ag(I)) and iodine usually employed in such reactions. We now report that in situ photolyses with visible light of several hydroxy compounds such as (-)-6,6-dimethylbicyclo[3.1.1]heptan-2β-ol [(-)-cis-nopinol] (1), 2-ethoxycarbonylmethyl-6,6-dimethylbicyclo[3.1.1]heptan-2β-ol (2), cedrol (5), isolongifolol /8), the hydrindane derivative (12), labdane-8α,15-diol (18), methyl 8α-hydroxylabdan-15-oate (19), labdanolic acid (20), methyl 3β-hydroxy-friedelan-29-oate (27) and friedelane-3b,30-diol 30-acetate (30) in the presence of (diacetoxyiodo)benzene and iodine lead to alkoxyl radicals which undergo intramolecular abstraction of suitably positioned hidrogen atoms to produce γ-functionalized derivatives.