Palladium(II)-Catalyzed Cascade Reactions of Ene–Ynes Tethered to Cyano/Aldehyde: Access to Naphtho[1,2‑b]furans and Benzo[g]indoles

An efficient palladium­(II)-catalyzed cascade reaction of ene–yne substrates carrying cyano/aldehyde group is described. It involves successive hetero- and benz-annulations in one pot via trans-oxo/aminopalladation onto alkyne, followed by 1,2-addition to cyano/aldehyde, providing a convenient synthesis of both naphtho­[1,2-b]­furans and benzo­[g]­indoles. The reaction constitutes a fast intramolecular assembly through several carbon–carbon and carbon–heteroatom bond formations taking place in one pot. The reactions are operationally simple, compatible with a range of functional groups and atom-economical in nature.