Catalyst-Free Synthesis of Benzofuran Derivatives from Cascade Reactions between Nitroepoxides and Salicylaldehydes.

Different benzofuran derivatives are synthesized via a catalyst-free reaction between nitroepoxides and salicylaldehydes. In the employed methodology, K2CO3 and DMF have been used at 110 °C, and the reactions were completed after 12 h in 33-84% yields. The highest yields were obtained using 3-nitrosalicylaldehyde. Finally, a plausible mechanism was proposed for the reaction, and some evidence was provided for this mechanism such as the detection of released acetate anion (using FTIR) and isolation and structure determination of the critical intermediate.