Biomimetic Total Synthesis of Gracilioethers B and C

Abstract

Total syntheses of the marine polyketide metabolites gracilioethers B and C have been realized in 9 steps (40% overall yield) and 10 steps (34% overall yield), respectively. The [2(5H)-furanylidene]ethanoate (furanylidene) motif was constructed in a transacetalization/dehydration cascade of an advanced β-ketoester intermediate, which was designed to mimic a postulated biosynthetic precursor to the natural products. The relative and absolute configurations of gracilioethers B and C are confirmed as (6R,8R) and (6R,8R,11S), respectively.

Marine natural products

“…The compound's relative conguration was also determined, 726,727 while the relative conguration of the C-36 to C-42 portion of hemicalide 1107 was also solved by synthesis. 728,729 Total syntheses of polyketides gracilioether B and C 730,731 and hippolachnin, 732,733 mycothiazole, [734][735][736] aromatic renieramycin I, 737,738 and peptides cyclocinamide A, 739 corticiamide B, [740][741][742] stylissamide X 743,744 and stylissatin A 745,746 have all been realised. The total synthesis of yaku'amide A 1108, including eight possible stereoisomers of its core region, required revision of structure, and also that of congener B 1109.…”

Spiroplakortone, an unprecedented spiroketal lactone from the Chinese sponge Plakortis simplex

“…20 Compound 2 would undergo aldolic addition by a-ketoisocaproate (3), deriving from transamination of leucine and, aer decarboxylation of the obtained product, a double cyclization could directly afford the target compound 1. A plausible polyketide precursor could be the b-ketoacid 2 (the likely ketide units are boldened), strictly related to the postulated precursor of another class of Plakortis metabolites, the furanylidene derivatives gracilioethers.…”

Functional Modules of Minimal Cell Division for Synthetic Biology

“…Redistributions of membrane components during cell division may create lipid domains as well as regions with highly concentrated proteins or protein coats, triggering membrane deformations that may contribute to accurate positioning of the division site and the force generated for successful septation. [98] Additionally, Mercier et al showed that increasing fluidity favors cell division in bacterial L-forms, suggesting that membrane fluidity might also modulate division. [99] Furthermore, it has been shown that the viscoelastic properties of lipid monolayers are modulated by FtsZ polymers.…”