✍ Scribed by Masayuki Takeuchi; Masahito Kodera; Koji Kano; Zen-ichi Yoshida
No coin nor oath required. For personal study only.
Mechanisms have been proposed for the (porphyrinato)iron(III)-catalyzed oxidation of styrene and a-methylstyrene by 0, in benzene-ethanol containing NaBH,. The product analysis and the deuterium incorporation using NaBD, suggest that the (u-alkyl)Fe"'-Por complex, [C,H,CH(CH,)]Fe"'-Par, is formed as an intermediate in the reaction of styrene. Insertion of 0, to the (a-alkyl)Fe"'-Por complex having a radical character yields a (peroxy)iron(III) complex, [C,H,CH(CH,)OO]Fe"'-Por.
The homolytic fission of the O-O bond followed by the hydrogen abstraction within the radical pair affords acetophenone and (HO)Fe"'-Por. Acetophenone is readily reduced with NaBH, to give I-phenylethanol. Meanwhile, the reaction of a-methylstyrene with BH, in the presence of Por-Fe"'C1 may also yield the (a-alkyl)Fe"'-Por complex, which takes up 0, to form a (peroxy)iron(III) complex, (C,H,C(CH,),OO)Fe"'-Por. The (peroxy)iron(III) complex is directly reduced by BH, to give 2-phenyl-2-propanol and (HO)Fe"'-Por.
In the reaction of styrene, such direct reduction of the (peroxy)iron(III) complex as a minor pathway competes with the homolytic fission of its O-O bond.
📜 SIMILAR VOLUMES