Bi(OTf)-Catalyzed Cascade Cycloaddition-Decarbonylation--Deoxygenative Aromatization between 2-Arylisatogens and Styrenes: Unveiling a Synthesis of 2,4-Diarylquinolines.

An unprecedented Bi(OTf)-catalyzed reaction between 2-arylisatogens and vinylarenes to yield 2,4-diarylquinolines is reported. The transformation occurred via a Bi-coordination to the embedded anionic nitrone oxygen, which induced a regiospecific stepwise formal [4 + 2]-cycloaddition with vinylarenes to yield a strained tricyclic intermediate, which subsequently extruded gaseous carbon monoxide. -Deoxygenative aromatization ensued to produce 2,4-diarylquinolines. The protocol was applicable to a variety of substrates to produce the quinolines in up to an 89% yield.