Homoadamantane polycyclic polyprenylated acylphloroglucinols from the fruits of Garcinia multiflora.

Five new homoadamantane polycyclic polyprenylated acylphloroglucinols (PPAPs, 1-5) were isolated from the fruits of Garcinia multiflora. Their structures and absolute configurations were determined by extensive spectroscopic analyses including NMR, HRESIMS and electronic circular dichroism (ECD). Compounds 1-3 possessed an unique core structure consisting of tetracyclo[7.3.1.13,11.03,7]tetradecane-2,12,14- trione. In comparison with those of 1-3, compound 4 had tricyclo[4.3.1.13,8]undecane- 2,9,11-trione with the loss of prenyl unit. Garcimultinone C (5) was the first example of seco-homoadamantane-type PPAPs with 5-oxatricyclo[7.3.1.03,7]tridecane skeleton derived from C(4)/C(5) carbon-carbon bond cleavage by retro-Claisen reaction.