Subporphyrins: emerging contracted porphyrins with aromatic 14π-electronic systems and bowl-shaped structures: rational and unexpected synthetic routes

Citations Over TimeTop 10% of 2008 papers

Abstract

Subporphyrin is a ring-contracted porphyrin congener consisting of three pyrrolic subunits domed in a C3 symmetric bowl arrangement. Subporphyrin had long been elusive until the first synthesis of tribenzosubporphine in 2006. Shortly after, synthetic protocols of subpyriporphyrin, meso-aryl-substituted subporphyrins, and meso-aryl substituted subchlorins were developed. Subporphyrins display interesting properties including distinct aromaticity arising from 14pi-electronic conjugation, green fluorescence, and strong influences of meso-aryl substituents on the electronic network of the macrocycle. Besides the rational synthetic routes, an unexpected route to a specific subporphyrin from a [32]heptaphyrin(1.1.1.1.1.1.1) was discovered via a thermal extrusion reaction upon Cu(II)-B(III) cooperative metallation. In this Perspective, we review recent progress on subporphyrin chemistry and unprecedented ring-splitting reactions of medium size expanded porphyrins that are triggered upon metallation.

Related Papers

• → A universal scale of aromaticity for π‐organic compounds(2009)53 cited
• → σ‐Aromaticity in an Unsaturated Ring: Osmapentalene Derivatives Containing a Metallacyclopropene Unit(2015)44 cited
• → σ Aromaticity Dominates in the Unsaturated Three‐Membered Ring of Cyclopropametallapentalenes from Groups 7–9: A DFT Study(2015)41 cited
• → Adaptive σ‐Aromaticity in an Unsaturated Three‐Membered Ring(2020)21 cited
• → Are nucleus-independent (NICS) and 1H NMR chemical shifts good indicators of aromaticity in π-stacked polyfluorenes?(2006)34 cited