Synthetic Studies of Archaeal Macrocyclic Tetraether Lipids: Practical Synthesis of 72-Membered Tetraether Model Compounds

Archaeal 72-membered macrocyclic tetraether model compounds (5 and 6) were synthesized by intramolecular dicarbonyl coupling with the aid of low-valent titanium, which is known as McMurry coupling. This synthetic methodology is the first practical way to obtain the two regioisomeric structures in quantity and appears to be applicable to the natural 72-membered tetraether lipids (3 and 4). Also described is the synthesis of the corresponding acyclic tetraether model counterparts (7 and 8) in reference to the cyclic lipids.