A high-yield, one-step synthesis of o-phenylene ethynylene cyclic trimer via precipitation-driven alkyne metathesis.

[reaction: see text] A shape-persistent, conjugated o-phenylene ethynylene cyclic trimer was prepared in one step from tetrasubstituted benzene monomer 4 in 86% isolated yield through precipitation-driven alkyne metathesis. The template-free, selective generation of the molecular triangle 5 is a thermodynamically favored process and under equilibrium control. A novel tetrameric macrocycle 7 was generated via scrambling metathesis between tricycle 5 and hexacycle 6 using this dynamic covalent chemistry.