Electrocyclization of arylvinyl β-hydroxyacetonitrile to substituted cyanomethyl indene derivatives

We have explored arylvinyl β-hydroxyacetonitrile as a 4π-electrocyclization precursor to access cyanomethyl indene in the presence of Lewis acids. Next, cyanomethyl indene was further reacted with an aromatic aldehyde to provide selective aryl/benzylation substitution on the indene ring. Furthermore, an electrocyclization reaction followed by selective benzylation of indene in one pot, as well as mechanistic studies to identify the source of hydrogen, was also conducted. Finally, we synthesized various substrates to demonstrate the substrate scope and limitation of this reaction, and the conversion of the nitrile group to its corresponding functional groups was also achieved, thereby expanding the scope of this approach.