Ligand‐Free Suzuki Cross‐Coupling Reactions: Application to β‐Halo‐α,β‐Unsaturated Aldehydes

A facile, efficient, ligand‐free Suzuki–Miyaura reaction of β‐halo α,β‐unsaturated aldehydes with boronic acids in aqueous media at room temperature is described. Under the optimized conditions, both steroidal and nonsteroidal β‐halo α,β‐unsaturated aldehydes reacted rapidly with the boronic acids to provide a series of aryl‐substituted derivatives in excellent yields. Moreover, the protocol was extended to the direct one‐pot synthesis of polycyclic aromatic hydrocarbons through a Suzuki–Miyaura cross‐coupling/aldol condensation cascade reaction under microwave irradiation.