Application of Electrochemically Generated Hypervalent Iodine Oxidant to Natural Products Synthesis

Hypervalent iodine oxidants have been widely applied in organic reactions due to their low toxicity, ready availability, and ease of handling. We produced an oxidant, [phenyliodine(III)bis(trifluoroethoxide)] (PIFE) by anodic oxidation of iodobenzene, which possesses comparable or superior properties to those of commercially available congeners, such as [phenyliodine(III)bis(trifluoroacetate)] (PIFA) and [phenyliodine(III)diacetate] (PIDA). The availability of PIFE was demonstrated by construction of several nitrogen-containing molecular skeletons; construction of quinolinone derivatives by PIFE occurred smoothly in moderate yield. In addition, the carbazole derivatives were synthesized in higher yields than with use of PIFA. Application of this methodology enabled synthesis of the bioactive tetrahydropyrroloiminoquinone-, carbazole-, and pyrroloindole-class natural products, including makaluvamines, damirones, glycozoline, debromofrustraminol B, and CPC-1. (C) The Electrochemical Society of Japan, All rights reserved.