Total Synthesis and Structure Confirmation of (E) and (Z)-Ocellenyne

Abstract

The (E/Z)-ocellenynes are C 15 dibrominated Laurencia natural products whose structures have been subject to several reassignments on the basis of extensive NMR analysis, biosynthetic postulates, and DFT calculations. Herein, we report the synthesis of both (E)-and (Z)-ocellenyne, which, in combination with single crystal X-ray diffraction studies, allows their absolute configuration to be established and defines the configuration of the syn-12,13-dibromide as being (S, S) in keeping with their proposed biogenesis from the (6S, 7S)-laurediols.

Marine natural products

“…Several first total syntheses of red algal metabolites were published in 2022, including those of C 15 acetogenins dehydroitomanallene B, 356 Z - 906 and E -ocellenyne 907 , which also established their absolute configurations, 357 sesquiterpenoid laurencenone C 358 and thysiferol-type triterpenoid saiyacenol A. 359 …”

“…354 Other structures were put forward although these were inconsistent with the spectroscopic data provided and are not shown here. 355 Several rst total syntheses of red algal metabolites were published in 2022, including those of C 15 acetogenins dehydroitomanallene B, 356 Z-906 and E-ocellenyne 907, which also established their absolute congurations, 357 sesquiterpenoid laurencenone C 358 and thysiferol-type triterpenoid saiyacenol A. 359 A review of the metabolites from the possibly invasive genus Acanthophora and of Asparagopsis, respectively, have been published, 360,361 as has a summary of red algal compounds with skin whitening cosmeceutical potential.…”