Productive Alkyne Metathesis with Canopy Catalysts Mandates Pseudorotation

Molybdenum alkylidyne complexes of the canopy catalyst series define new standards in the field of alkyne metathesis. The tripodal ligand framework lowers the symmetry of the metallacyclobutadiene complex formed by [2 + 2] cycloaddition with the substrate and imposes constraints onto the productive [2 + 2] cycloreversion; pseudorotation corrects this handicap and makes catalytic turnover possible. A combined spectroscopic, crystallographic, and computational study provides insights into this unorthodox mechanism and uncovers the role that metallatetrahedrane complexes play in certain cases.

Automated summary

Molybdenum alkylidyne complexes of the canopy catalyst series set new standards in alkyne metathesis by utilizing an unorthodox mechanism, with the tripodal ligand framework playing a crucial role in the formation and reversal of metallacyclobutadiene complexes.