Structural elucidation of a hy­droxy–cineole product obtained from cytochrome P450 monooxygenase CYP101J2 catalysed transformation of 18-cineole

摘要

1,8-Cineole is an abundant natural product that has the potential to be transformed into other building blocks that could be suitable alternatives to petroleum-based chemicals. Mono­hydroxy­lation of 1,8-cineole can potentially occur at eight different carbon sites around the bicyclic ring system. Using cytochrome P450 monooxygenase CYP101J2 from Sphingobium yanoikuyae B2, the hy­droxy­lation can be regioselectively directed at the C atom adjacent to the methyl-substituted quaternary bridgehead atom of 1,8-cineole. The unambiguous location of the hydroxyl functionality and the stereochemistry at this position was determined by X-ray crystal analysis. The mono­hydroxy­lated compound derived from this microorganism was determined to be (1S)-2a-hy­droxy-1,8-cineole (trivial name) or (1S,4R,6S)-1,3,3-trimethyl-2-oxabi­cyclo­[2.2.2]octan-6-ol (V) (systematic), C10H18O2. In the solid state this compound exhibits an inter­esting O—H⋯O hydrogen-bonding motif.