β-Triketones from Myrtaceae: Isoleptospermone from Leptospermum scoparium and Papuanone from Corymbia dallachiana

Abstract

Naturally occurring β-triketones, isoleptospermone [3, 5-hydroxy-4-(2-methyl-1-oxopentyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione) from Leptospermum scoparium] and papuanone [6, 5-hydroxy-4-(1-oxohexyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione from Corymbia dallachiana], have been synthesized. Full spectral data are reported for the first time. The ¹³C NMR spectra of 3, 6, and the other triketones flavesone (2), leptospermone (4), and grandiflorone (5) found in Myrtaceous plants are fully assigned.