An expedient route to tricyanovinylindoles and indolylmaleimides from o-alkynylanilines utilising DMSO as a one-carbon synthon†
Nikita Chakraborty,Anjali Dahiya,Amitava Rakshit,Anju Modi,Bhisma K. Patel
Organic & Biomolecular Chemistry Pub Date : 07/20/2021 00:00:00 , DOI:10.1039/D1OB01086G
Abstract

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 C[double bond, length as m-dash]C 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.

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