Total Synthesis of Archaeal 36-Membered Macrocyclic Diether Lipid

Abstract

Total synthesis of archaeal 36-membered macrocyclic diether lipid 2 is reported. The synthesis is based upon stereoselective preparation of functionalized isoprenoid chains, ether-linkage formation between the isoprenoid chains with a glycerol derivative, and the ultimate intramolecular dicarbonyl coupling using low-valent titanium known as McMurry coupling. This synthetic method has successfully provided the first practical route to chemically defined archaeal macrocyclic membrane lipids, which were not available because of the lack of synthetic access. Also described is a highly stereoselective and convenient synthesis of stereochemically homogeneous archaeal biphytanyl glycerol lipid 1.

Synthesis and aggregation behaviour of symmetric glycosylated bolaamphiphiles in water

“…The critical aggregation concentrations (CAC) were determined either by measuring their superficial tension vs concentration, or by the dye method in spectrofluorimetry (with pyrene) or in colorimetry, according to Menger's method with pinacyanol chloride. 4 Determined by ffem 5 Determined by surface tension measurement Type A compounds bearing a ten carbon atom hydrophobic portion did not show any visible objects on the images obtained by FFEM, regardless of the number of galactosylated units grafted on the polar head (figure not shown). This observation indicates the absence of supramolecular organisations larger than very small micelle-like aggregates.…”

“…2,3 In order to withstand these extreme living conditions, the hydrophobic chains which form the lipid bilayer of their cell membranes are fused, creating macrocyclic molecules not easily synthesised in a laboratory. 4 For 30 years, the scientific community has been trying to synthesise lipid analogues capable of forming non-merging vesicle membranes. From this point of view, considering the slower rate of the membrane fusion phenomenon in monolamellar membranes, the bolaform surfactants represent a good alternative and archaeal membranes have begun to be used in the pharmaceutical preparation of liposomes.…”

Determination of the Configuration of an Archaea Membrane Lipid Containing Cyclopentane Rings by Total Synthesis

“…[4] In fact, the configuration of the macrocyclic tetraether A has been determined by total synthesis of the diol C and comparison with a sample of C obtained by degradation of natural A. [5] In the meantime, a synthesis of A has also been carried out.…”

Highly Enantioselective Rhodium‐Catalyzed Hydrogenation of 2‐(2‐Methoxy‐2‐oxoethyl)acrylic Acid − A Convenient Access of Enantiomerically Pure Isoprenoid Building Blocks

“…Most often the lactones (S)-A1 and (S)-A2 were used, for example for syntheses of α-tocopherol, [1b,1c] vitamin K 1 , [2] mammalian dolichols, [3] Archaea membrane lipids, [4] (S)-26-hydroxycholesterol [5] and (ϩ)-invictolide. [6] Widely differing methods were employed for syntheses of these synthons.…”