ChemInform Abstract: Electron and Hydrogen Atom Transfer Mechanisms for the Photoreduction of o-Quinones. Visible Light Induced Photoreactions of β-Lapachone with Amines, Alcohols, and Amino Alcohols.
Abstract
In the presence of amines such as triethylamine (II) the title reaction of (I) proceeds via the triplet state as a sequence of two electron transfer-proton transfer steps leading to the semiquinone radical (III) and the enamine (IV).
ChemInform Abstract
In the presence of amines such as triethylamine (II) the title reaction of (I) proceeds via the triplet state as a sequence of two electron transfer-proton transfer steps leading to the semiquinone radical (III) and the enamine (IV). In the case of amino alcohols such as erythroor threo-(V) a concurrent C-C cleavage occurs. In the presence of alcohols such as benzyl alcohol the oxidation of the excited alcohol is observed in addition to (III), leading to the aldehyde (VI) as well with low efficiency due to inefficiencies of net H-atom transfer in the quenching step (strong dependence of the reaction efficiency on the concentration of (I) in all three cases; ESR, fluorescence, UV/VIS).
