Discovering a Racemate Polycyclic Prenylated Acylphloroglucinol with Unprecedented Skeleton by an ESI-LCMS Analytical Approach

By an ESI-LC/MS analytical method, a racemate 1 consisting of a pair of unprecedented phloroglucinol enantiomers with a 5/6/5/5/6 fused ring system, (−)-garcinielliptone HG [((−)-1a] and (+)-garcinielliptone HH [(+)-1b], was obtained from the isolates of a CH2Cl2 extract of Garcinia subelliptica (heartwood). The gross structure of 1 was elucidated by spectroscopic methods and X-ray single-crystal diffraction data. The absolute configurations of 1a and 1b were unequivocally assigned by analysis on the calculated and experimental circular dichroism spectra and X-ray single-crystal diffraction data.