Cobalt Octacarbonyl-Catalyzed Scalable Alkyne Cyclotrimerization and Crossed [2 + 2 + 2]-Cycloaddition Reaction in a Plug Flow Reactor

Cobalt-catalyzed alkyne cyclotrimerization and crossed [2 + 2 + 2] cycloadditions are developed in a plug flow reactor. The protocol generally uses 5 mol % of Co₂(CO)₈ and is scalable at least at multigram scale. Efficient and scalable use of Co₂(CO)₈ for crossed reactions of diynes and alkynes has hardly any precedent.