Intramolecular cyclization and disilylation of 1,1-dicyano-2,2-diarylethenes promoted by samarium/TMSCl in DMF: a new approach to the syntheses of polysubstituted indenes

Promoted by samarium metal in DMF and in the presence of TMSCl, 1,1-diaryl-2,2-dicyanoethylenes undergo an unexpected kind of reductive cyclization, thus affording a new approach to the construction of indene core. Simultaneously, disilylation occurred at the amino moiety resulting from the reduction of the cyano group.