ABSTRACT
We developed an electrochemical strategy for the synthesis of quinones through direct oxidation of widely accessible arenes and heteroarenes under mild conditions. A variety of quinones and hetero quinones were prepared with moderate to good yields, without the involvement of the pre-functionalized substrates. In addition, this atom economic method also exhibits wide functional group tolerance, including C(sp2)-I bond, ester, aldehyde, and OTf groups. This synthetic approach provides a straightforward and atom economic method for the transformation of C(sp2)-H bonds.
Subject(s)
Quinones , Oxidation-ReductionABSTRACT
A three-component reductive coupling reaction of aldehydes, amines and cyanopyridines under electrochemical conditions has been developed. The in situ generated imine and cyanopyridine simultaneously undergo single-electron reduction at the cathode, and afford diarylmethylamines through radical coupling without the participation of reducing agents. The one-pot electrolysis method can modularly obtain various secondary and tertiary amines and exhibits broad functional group compatibility. Mechanistic experiments verify the pivotal reduction step from imine to α-amino radical and reveal the key role of benzoic acid in reducing the reduction potential of imine and cyanopyridine.