Photo-induced spirocyclization of biaryl ynones with ammonium thiocyanate: access to thiocyanate-featured spiro[5,5]trienones

Abstract

Photo-promoted mild tandem 6-exo-trig spirocyclization of biaryl ynones with ammonium thiocyanate has been developed to access thiocyanate-containing spiro[5,5]trienones with good yields and regioselectivity. Meanwhile, other thiocyanate-substituted cycles also could be produced under similar conditions. The merits and reaction process of this radical system were examined by a variety of scaled-up operations, functional group transformations, intermediate capture study, and on/off light experiments.