An expedient route to tricyanovinylindoles and indolylmaleimides from o-alkynylanilines utilising DMSO as a one-carbon synthon

A Pd(II)/Cu(II) catalysed domino synthesis of tricyanovinylindoles has been achieved using DMSO as a one-carbon synthon. The reaction proceeds via the construction of 2-aryl-3-formyl indole followed by sequential addition of malononitrile and a CN resulting in two C–C, one CC and one C–N bonds in the final product. Furthermore, post-synthetic modification results in the unprecedented formation of 4-cyano-3-indolylmaleimides. Photophysical studies of selected compounds show emission in the visible range.