Isomerisation of alpha-pinene oxide in the presence of indenyl allyl dicarbonyl molybdenum(II) and tungsten(II) complexes

The indenyl complexes IndM(eta(3)-C3H5)(CO)(2) (M= Mo (1), W (2)), (IndMe)Mo(eta(3)-C3H5)(CO)(2) (3) and (IndSiMe(3))Mo(eta(3)-C3H5)(Co)(2) (4) display catalytic activity for the isomerisation of alpha-pinene oxide. Conversion reached 97% after 3 h at 35 degrees C in the presence of 1 and 1,2-dichloroethane as solvent, giving campholenic aldehyde in 56% yield. Solvent polarity and basicity appear to affect the reaction rate. Whereas the type of substituent on the indenyl ligand does not appear to have a strong impact on catalytic performance, changing the metal centre from Mo (1) to W (2) gave a significantly more active catalyst.