The rhodium-catalyzed Pauson–Khand reaction

A rhodium carbonyl complex, [RhCl(CO)2]2, serves as a catalyst of the intra- and inter-molecular Pauson–Khand reaction. By the use of the rhodium catalyst, cyclopentenone derivatives are prepared from various 1,6- and 1,7-enynes under 1 atm of CO. Furthermore, this rhodium-catalyzed reaction is accelerated by reducing partial pressure of CO to less than 1 atm.