Access to Diverse Seleno-spirocyclohexadienones via Ag(II)-Catalyzed Selenylative -Annulation with Se and Boronic Acids.

An efficient and straightforward synthesis of diversified seleno-azaspiro-2,5-cyclohexadienones from -(4-methoxy aryl)propiolamides using elemental selenium and boronic acids has been demonstrated. The reaction proceeds through silver-catalyzed oxidative dearomatization in the presence of potassium persulfate (KSO) as the oxidant. Further, this approach was extended to -(4-methoxy aryl)propiolates and biaryl ynones to access the corresponding selenylated oxospiro-2,5-cyclohexadienones and spiro[5,5]trienones, respectively. The present three-component method offers the diverse substitutions on selenium involving two C-Se and one C-C bond formations.