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.

The archaebacterial macrocyclic diether lipid featuring a 36-membered ring is synthesized by the McMurry coupling as a key step.Archaebacterial membrane lipids are structurally unique in that the glycerol core is linked to isoprenoid chains with ethereal bonding, compared to the ester linkage with fatty acids found in eubacterial and eukaryotic membrane lipids. These unusual lipids have attracted attention in connection with their physicochemical properties. Several modelling and synthetic studies have been reported in order to investigate the stability, fluidity and permeability of the archaebacterial membrane lipids.2 The most striking feature of the archaebacterial ether lipid is found in the macrocyclic ring structures. Recently, we reported a highly efficient method for macrocyclic ring formation based on the McMurry coupling directed toward the macrocyclic archaebacterial membrane lipids.3

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Total Synthesis of Archaeal 36-Membered Macrocyclic Diether Lipid.-The synthesis of the title lipid (I) is based on stereoselective preparation of functionalized isoprenoid chains, ether-linkage formation between these chains with a glycerol derivative, and the ultimate intramolecular dicarbonyl coupling using low-valent titanium McMurry coupling as key steps. -(EGUCHI, T.; ARAKAWA, K.; TERACHI, T.; KAKINUMA, K.; J.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.