Total syntheses of (+)-spiculoic acid A and (+)-zyggomphic acid, new marine natural products of polyketide origin

Elaboration of Sterically Hindered δ-Lactones through Ring-Closing Metathesis: Application to the Synthesis of the C1–C27 Fragment of Hemicalide

“…Hence, addition of an excess of citric acid into the reaction medium, while adjusting the quantity of potassium osmate (K 2 OsO 4 .2H 2 O) to 2 mol %, provided the expected pure cis -1,2-diol 32 in 70% yield. Finally, protection of the diol as a bis -triethylsilyl ether (formation of 33 in 96% yield) followed by palladium-catalyzed borylation with bis- pinacolato-diboron 34 delivered the trisubstituted ( E )-alkenylboronate 13 in 66% yield (Scheme ).…”

Marine natural products

“…459 The total synthesis and conrmation of absolute conguration of (+)-zyggomphic acid (P. zyggompha) 460 was achieved. 461 Diketopiperazine 592 came from Stelletta sp. (Jamieson Reef, Bonaparte Archipelago, Australia).…”

Recent Applications of Phosphane-based Palladium Catalysts in Suzuki-Miyaura Reactions Involved in Total Syntheses of Natural Products

“…It should be noted that compound C72 had previously been employed in the first synthesis of compound 391 (Figure 21), a degradation product of the alkaloid (-)lycorine (390) ( Figure 21 Again in 2011, the first total syntheses of the cytotoxic marine natural products (+)-spiculoic acid (326) and (+)zyggomphic acid (327) were accomplished on the basis of the retrosynthetic analysis depicted in Scheme 92 in which the central feature was the highly stereoselective and high yielding intramolecular Diels-Alder reaction of the (E,E,E)dodecatrienal derivatives 392 and 393, respectively. [309] These compounds were obtained by Dess-Martin oxidation of the cross-coupling products C73 and C74, respectively, which were synthesized by the stereoselctive S.-M. reactions reported in entries 26 and 27 of Table 9, respectively. [309] (E)-Vinylboronates A75 and A76, which were employed in these cross-couplings, were in turn synthesized from known enantiomerically pure (S) Table 9).…”

“…[309] These compounds were obtained by Dess-Martin oxidation of the cross-coupling products C73 and C74, respectively, which were synthesized by the stereoselctive S.-M. reactions reported in entries 26 and 27 of Table 9, respectively. [309] (E)-Vinylboronates A75 and A76, which were employed in these cross-couplings, were in turn synthesized from known enantiomerically pure (S) Table 9). Compound A77 was prepared in 64% yield by the PdCl2(dppf)-catalyzed boronation of methyl 3-bromo-4methoxybenzoate (395) with bis(pinacolato)diboron (Scheme 93).…”