Development and Application of Highly Chemoselective Organic Reductants

Several viologen derivatives (1,1'-disubstituted 4,4'-bipyridynium, V^<2+>) were synthesizedand their electrochemical behavior was studied to reveal that 1) two one-electron reductionprocesses occurred on V2^+ to give V^<+·> and V^0, stepwise，V^0s worked as organic reductants compatible to zinc. V^0 were generated by electroreductionof v ^< 2 +>,and promoted Pd-catalyzed reductive coupling of aryl halides to give the corresponding biaryls. Byproper choice of substituents on N of V^<2+>，V^0 could be used in several media such as usual organic solvents, ionic liquidsand water. Moreover，electroreduction of N-substituted pyridinium derivatives also gave organic reductants。

Several viologen derivatives (1,1'-disubstituted 4,4'-bipyridynium, V^<2+>) were synthesized, and their electrochemical behavior was studied to reveal that 1) two one-electron reduction processes occurred on V2^+ to give V^<+・> and V^0, stepwise, and 2) V^0s worked as organic reductants compatible to zinc. V^0 were generated by electroreduction of V^<2+>, and promoted Pd-catalyzed reductive coupling of aryl halides to give the corresponding biaryls. By proper choice of substituents on N of V^<2+>, V^0 could be used in several media such as usual organic solvents, ionic liquids, and water. Moreover, electroreduction of N-substituted pyridinium derivatives also gave organic reductants.