Proof-of-principle direct double cyclisation of a linear C₁₅-precursor to a dibrominated bicyclic medium-ring ether relevant toLaurenciaspecies

Abstract

Bicyclic dibrominated C15 medium-ring ether hexahydrolaureoxanyne was produced directly from an acyclic model C15-epoxide when treated with NBS with water as the solvent.

Carnitine palmitoyltransferase gene upregulation by linoleic acid induces CD4+ T cell apoptosis promoting HCC development

“…Ethyl 11-hydroxyundec-9-ynoate was brominated and coupled with compound 4 in the presence of copper (I) catalyst and cesium carbonate to provide the fluorescent diyne product 7. The two alkynes group of compound 7 were hydrogenated to Z,Z-diene 8 using Lindlar’s catalyst 44 , 45 . Subsequently, compound 8 was hydrolyzed under aqueous hydrochloride acid to produce the final probe LAP1.…”

Forwards and backwards – synthesis of Laurencia natural products using a biomimetic and retrobiomimetic strategy incorporating structural reassignment of laurefurenynes C–F

“…[20][21][22] Key to correcting many of these structural misassignments have been postulates regarding the biosyntheses of acetogenic Laurencia natural products, many of which have been proposed to proceed through complex oxonium ion intermediates. 15,[23][24][25][26][27][28][29][30][31][32][33] These biogenetic postulates have allowed rational prediction of the likely structures of a number of the natural products 15,21,22,26,34 and in a number of cases the biogenetic arguments have been augmented by DFT calculations of both proton and carbon NMR chemical shis 14,22,34 for a range of candidate structures with ultimately the structure of the natural products being established through total synthesis. 35 Among the acetogenic Laurencia natural products whose structures have been reassigned are laurefucin, 36,37 obtusallenes V, VI and VII, 16,19,26 elatenyne, [12][13][14][15]38 laurendecumenyne B, 15,39,40 aplysiallene, 41,42 a chloroenyne from Laurencia majuscula 13,34,38,43 and laur...…”

Pinnatifidenyne-Derived Ethynyl Oxirane Acetogenins from Laurencia viridis

“…Medium-ring haloethers of Laurencia , a significant subset of biologically active marine natural products [ 1 , 2 ], continue to challenge innovative efforts as attractive targets for the synthesis of stereochemically rich medium-sized oxacyclic compounds [ 3 , 4 ] or to explore biogenetic hypothesis [ 5 , 6 ].…”