Rh( iii )-catalyzed oxidative C–H annulation of 6-arylpyridazin-3(2 H )-ones: direct access to diarylpyridazino[6,1- a ]isoquinolin-5-ium-3-olates

A novel synthesis of pyridazino[6,1- a ]isoquinolin-5-ium-3-olate derivatives is described using a Rh( iii )/AgSbF 6 catalytic system. This is the first report on ortho -C–H bond annulation of 6-arylpyridazin-3(2 H )-ones with disubstituted alkynes.