Syntheses of Carbaporphyrinoid Systems Using a Carbatripyrrin Methodology

A carbatripyrrin intermediate was prepared from commercially available technical-grade indene and 2-pyrrolecarbaldehyde in three steps and 50% overall yield. This novel conjugated structure reacted with pyrroledialdehydes and 2,5-furandicarbaldehyde in the presence of TFA to give good yields of carbaporphyrins and an oxacarbaporphyrin, respectively, and unlike currently available methodologies, no oxidation step was required. The carbatripyrrin also condensed with heterocyclic dicarbinols in the presence of BF3·Et2O to give a series of heterocarbaporphyrins.