Effect of carbinol group placement on complementary reactions of dipyrromethane+bipyrrole species leading to corrole and/or an octaphyrin

Complementary reactions of a dipyrromethanedicarbinol+2,2′-bipyrrole and a 2,2′-bipyrroledicarbinol+a dipyrromethane were investigated to determine the effect of carbinol group placement on the product distribution and on the broader reaction course. Analytical-scale reactions were performed for both reactions to explore the interplay of acid catalyst, acid concentration, and solvent on the yield of corrole and an octaphyrin. The two reaction routes were further compared under representative conditions by assessing acid-catalyzed decomposition of the dicarbinol species affording benzaldehyde (TLC and GC-MS) and by performing time course experiments monitoring macrocycle yield (UV-vis), presence of benzaldehyde (TLC), and oligomer composition (LD-MS). The complementary reactions were generally found to be quite different. Key to this work was the refinement of a method for the acylation of 2,2′-bipyrrole.