Survey of the two-step, one-flask reaction of 5-pentafluorophenyldipyrromethane with a 5,5-dimethyldipyrromethanedicarbinol species bearing pentafluorophenyl substituents

ORGN 546

Anna Y. O'Brien, ggeier@mail.colgate.edu and G. Richard Geier III. Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, NY 13346
Acid catalyzed condensation followed by oxidation (two-step, one-flask method) of 5-pentafluorophenyldipyrromethane with a 5,5-dimethyldipyrromethanedicarbinol species bearing pentafluorophenyl substituents was investigated. The target compound is a phlorin macrocycle possessing electron-withdrawing substituents. Phlorin is an analog of porphyrin that has an sp3 hybridized carbon atom at one of the four bridging meso-positions. The current work complements our ongoing efforts to prepare stable phlorins via the judicious selection of peripheral meso-substituents. The required dipyrromethane and diacyldipyrromethane building blocks were prepared. A systematic examination of acid catalysts, acid concentration, condensation time, and oxidation conditions on the reaction of the dipyrromethane and dipyrromethanedicarbinol was performed via analytical scale reactions monitored by HPLC.