Iron(II)-catalyzed annulation to construct novel quinone-fused cyclopenta[2,1-b]indoles: A promising Type I photosensitizer

Novel quinone-fused cyclopenta[2,1- b ]indoles, promising Type I photosensitizers, were conveniently constructed by an iron( ii )-catalyzed annulation, exhibiting near-infrared absorption, producing O 2 ˙ − and showing excellent effects in tumor cells.