[(1R)-2,2,3-trimethyl-5-oxocyclopent-3-en-1-yl]acetate + H(+) => (1S,4S)-5-oxo-1,2-campholide
[(1r)-2,2,3-trimethyl-5-oxocyclopent-3-en-1-yl]acetate + h(+) => (1s,4s)-5-oxo-1,2-campholide
[(1R)-2,2,3-trimethyl-5-oxocyclopent-3-en-1-yl]acetate + H(+) => (1S,4S)-5-oxo-1,2-campholide
[(1r)-2,2,3-trimethyl-5-oxocyclopent-3-en-1-yl]acetate + h(+) => (1s,4s)-5-oxo-1,2-campholide