Isomerization of α-pinene oxide in the presence of methyltrioxorhenium(VII)

The catalytic performance of methyltrioxorhenium(VII) (MTO) has been investigated for the first time in the isomerization of α-pinene oxide (PinOx) into campholenic aldehyde (CPA). The high isomerization activity of MTO is coupled with high selectivity to CPA: CPA yield of up to 87% (100% conversion) was obtained by using α,α,α-trifluorotoluene as solvent at 15 C. Catalyst recycling is possible in a relatively simple fashion by using MTO coupled to an appropriate ionic liquid. The catalytic application of MTO in the isomerization of PinOx versus the integrated epoxidation- isomerization process of the conversion of α-pinene into CPA is discussed.