The first total synthesis of polyhydroxylated cyclohexenone 1, isolated from Pleiogynium timorense and named pleiogenone A, is reported that also serves as a proof of structure and absolute configuration. Enzymatic dihydroxylation of benzoic acid with R. eutrophus B9 provided enantiomerically pure diene diol 6. Elaboration of the carboxylate moiety to the alkyl side chain was followed by singlet oxygen cycloaddition to furnish an endoperoxide whose reduction with thiourea led to cyclitol 19. Several protective operations were required before oxidation and the final extension of the side chain by a Wittig reaction. After final deprotection of the acetonide functionality the desired pleiogenone A (1) was obtained in 14 operations from benzoic acid.

Natural Products Pleiogenone A, which has been isolated from Pleiogynium timorense, has been synthesized for the first time. The synthesis confirms the previously reported structure as well as the absolute configuration. The route started with the enzymatic dihydroxylation of inexpensive and readily available benzoic acid by R. eutrophus B9. For more details, see the Full Paper by T. Hudlicky et al. on page 6180 ff. Jordan Froese and Dennis Ceci, both at Brock University, are acknowledged for the design of the Frontispiece.

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