Isolation and characterization of two geometric allene oxide isomers synthesized from 9S-hydroperoxylinoleic acid by cytochrome P450 CYP74C3: Stereochemical assignment of natural fatty acid allene oxides

Abstract

Background: Allene oxides involved in cyclopentenone biosynthesis are extremely labile and have eluded full stereochemical assignment. Results: We identify a novel Z-allene oxide that unexpectedly rearranges to a cyclopentenone. Conclusion: Other natural allene oxides are assigned the E configuration and can be easily distinguished from the Z-allene oxide by NMR. Significance: Unequivocal determination of the unknown allene oxide configuration is documented and helps elucidate the cyclization chemistry. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.