Photochromic difurylethene bisaldehyde as potential building block for [AA] and [AB]2 macrocyclization

Catalyst- and template-free condensation of photochromic difurylethene bisaldehyde with o-phenylenediamine led to selective formation of macrocyclic Schiff base [AB](2) product. Application of the same difurylethene bisaldehyde in the McMurry reaction resulted in cyclic dimer formation in moderate yield. No linear oligomers were observed in both approaches.