β-Linked dipyrroalkanes as potential precursors to conformationally restricted bipyrroles and tetrapyrrolic macrocycles

CHED 504

Margaret Collins, Amanda N. Samuels, and G. Richard Geier III, ggeier@mail.colgate.edu. Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, NY 13346
β-Linked dipyrroalkanes are compounds comprised of two pyrrole rings connected at β-positions by a straight chain alkane. In our previous work, we developed methodology for the preparation of β-linked dipyrrobutane, dipyrropentane, and dipyrrohexane. We are presently seeking to determine whether such species can serve as precursors to conformationally restricted 2,2¢-bipyrroles or as building blocks to tetrapyrrolic macrocycles. Attempts to the prepare conformationally restricted 2,2¢-bipyrroles via the oxidation of β-linked dipyrrobutane and dipyrrohexane were performed by surveying a variety of oxidants and reaction conditions. Attempts to prepare tetrapyrrolic macrocycles from the two-step, one-flask reaction of the same β-linked dipyrroalkanes with benzaldehyde were also carried out with a systematic investigation of key reaction parameters. The results of both studies will be presented.