Stable catalyst for intermolecular Pauson–Khand reaction

The catalytic activity of previously formed Co2(CO)6[P(Ph)3]2 (1) was compared with Co2(CO)8 and the system formed by Co2(CO)8 plus PPh3 in the intermolecular Pauson–Khand (PK) reaction between norbornadiene and phenylacetylene. The effects of pressure, catalyst concentration and temperature were also studied. Additionally, the catalytic activity of complex 1 was compared with Co2(CO)6[P(OPh)3]2 (2) in the intermolecular PK reaction between strained alkenes and terminal and non-terminal alkynes. Both catalysts are very stable, quite efficient and interestingly complex 2 leads to double PK reaction. The results indicate that these complexes are attractive alternatives to Co2(CO)8 as catalyst and in addition, complex 2 is an alternative catalyst for double cyclocarbonylation reaction.

Graphical abstractDetailed accounts of intermolecular Pauson–Khand reaction catalyzed by two stable Co2(CO)6[P(Ph)3]2 (1) and Co2(CO)6[P(OPh)3]2 (2) complexes, have been described. The results indicate that these complexes are attractive alternatives to Co2(CO)8 as catalyst and in addition, complex 2 is an alternative catalyst for double cyclocarbonylation reaction. Figure optionsDownload full-size imageDownload as PowerPoint slide