Total synthesis of cis-reticulatacin-10-ones A and B: absolute stereochemical assignmentElectronic supplementary information (ESI) available: Preparation of all novel compounds and copies of 1H and 13C NMR spectra and chromatograms. See DOI: 10.1039/c0ob00259c

cis -Reticulatacin-10-ones A and B were synthesised as a predefined mixture of diastereoisomers (dr ∼ 1 : 9) in nine steps from the acid chloride 8 , and without the use of hydroxyl protecting groups. Comparison of the chiral HPLC chromatogram of the synthetic sample with that of the natural product isolated from the roots of the tropical fruit tree Annona muricata L. showed the natural product to be a mixture of A and B diastereoisomers (dr ∼ 1 : 1). The natural product cis -reticulaticin-10-one, isolated from Annona muricata L., was shown to be a mixture of A (17 R ,18 R ,21 S ,22 S ,36 S ) and B (17 S ,18 S ,21 R ,22 R ,36 S ) diastereoisomers by using chiral HPLC to compare the natural isolate with standards prepared by total synthesis.