Synthesis of star-shaped pyrrole-based C3-symmetric molecules via ring-closing metathesis, Buchwald–Hartwig cross-coupling and Clauson–Kaas pyrrole synthesis as key steps

Abstract

We have demonstrated three contrasting synthetic strategies to assemble pyrrole-based C3-symmetric molecule. Here, ring-closing metathesis (RCM), Buchwald–Hartwig cross-coupling and Clauson–Kaas pyrrole synthesis have been used as key steps. Interestingly, readily available starting materials such as 4-aminoacetophenone, 4-bromo acetophenone and 4-nitro acetophenone have been used as starting materials. Grubbs’ first generation catalyst (G-I) is useful for one-pot RCM and aromatization sequence without the involvement of additional reagents. We also report photophysical properties of these star-shaped molecules.