Electrochemical C-H Amidation of Heteroarenes with N-Alkyl Sulfonamides in Aqueous Medium.

ABSTRACT

The construction of C-N bonds by free radical reactions represents a powerful synthetic approach for direct C-H amidations of arenes or heteroarenes. Developing efficient and more environmentally friendly synthetic methods for C-H amidation reactions remains highly desirable. Herein, metal-free electrochemical oxidative dehydrogenative C-H amidations of heteroarenes with N-alkylsulfonamides have been accomplished. The catalyst- and chemical-oxidant-free C-H amidation features an ample scope and employs electricity as the green and sole oxidant. A variety of heteroarenes, including indoles, pyrroles, benzofuran and benzothiophene, thereby underwent this C(sp2 )-H nitrogenation. Cyclic voltammetry studies and control experiments provided evidence for nitrogen-centered radicals being directly generated under metal-free electrocatalysis.