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...

A metal/peroxide-free involved simple cascade 6-exo-trig spirocyclization of tert-butyl nitrite with biaryl ynones has been finished, which resulted in various NO2-modified spiro[5,5]trienones with good regioselectivity/yields. A variety of scaled-up experiments, reduction/epoxidation operations, and mechanistic studies were performed to verify the merits and spirocyclization process of this radical system. Finally, the structure of the spirocycles was confirmed by single-crystal X-ray diffraction.