MeSiBr-promoted cascade electrophilic thiocyanation/cyclization of -alkynylanilines to synthesize indole derivatives.

A Lewis acid-promoted electrophilic thiocyanation/cyclization of -alkynylanilines for the synthesis of indole derivatives has been developed. The reaction utilizes MeSiBr as the Lewis acid and -thiocyanatosuccinimide as the thiocyanation reagent. A series of 2-aryl-3-thiocyanato indoles were prepared in moderate to high yields under mild conditions without metals and oxidants. It provides an efficient protocol for the construction of the indole skeleton and C-SCN and C-N bonds in one step as well.