Structures of the GDGT lipids described in this study. The carbons on glycerol moieties are marked (1-3) according to stereochemical numbering (sn) convention. It is notable that in isocaldarcheaol, the isopranoid chains are linked in a parallel fashion (2 → 2′ and 3 → 3′). The glucosyl derivatives were synthesized as mixtures of anomers.