A novel aerobic catalytic oxidation system for the sulfenylation of indoles with a
variety of sulfenylation agents through oxidative C–S bond coupling has been successfully
developed. The reactions were performed with potassium iodide as the catalyst, sodium
nitrite as the co-catalyst, and molecular oxygen as the terminal oxidant in the presence
of acetic acid. Under the optimal reaction conditions, a number of indoles could be
sulfenylated with Bunte salts, thiols, or disulfides to generate 3-sulfenylindoles
in good yields. This protocol provided an efficient and environmentally benign strategy
for the synthesis of 3-sulfenylindoles.
Key words
indoles - sulfenylation - C–S bond coupling - catalytic oxidation - regioselectivity
