1‐Phospha‐Butadienes and 1H‐Phospholes via Alkynylation of Acetylenic Phosphaalkenes

Abstract

Carbon‐rich motifs are important building blocks for the fabrication of functional and opto‐electronic materials. Electronic tuning can be achieved by alteration of bonding topologies but also via incorporation of heteroelements, for example phosphorus. Herein we present the palladium/copper mediated formation of branched 1‐phospha‐butadiene derivatives through an unusual alkynylation of a phospha‐enyne fragment. Structural and NMR studies provide mechanistic insights into this alkynylation. Furthermore, we disclose a complex cyclisation of the thus obtained 3‐yne‐1‐phosphabutadiene motifs to give highly substituted phosphole derivatives identified by 2D NMR and SC‐XRD analysis.