Pd-Catalyzed Cyanoselenylation of Internal Alkynes: Access to Tetrasubstituted Selenoenol Ethers.

The intra- and intermolecular synthesis of selenium-substituted acyclic and heterocyclic acrylonitrile derivatives is presented. The 1,2-difunctionalization of several internal alkynes substituted not only by aliphatic and aromatic residues but also by heteroelements is realized by the Pd-catalyzed activation of aromatic and aliphatic selenocyanates. A high functional group tolerance allows straightforward access to a broad scope of tetrasubstituted olefins. X-ray studies of some products reveal noncovalent chalcogen-chalcogen interactions between oxygen and selenium.