Simple and modestly scalable synthesis of iso-Cyrene from levoglucosenone and its comparison to the bio-derived and polar aprotic solvent Cyrene®

The bio-derived platform molecule levoglucosenone (LGO, 1), which is the precursor to the green solvent Cyrene® (2), has been converted, at multi-gram scale, into its pseudo-enantiomer (iso-LGO, 2) and then reduced to iso-Cyrene (4). A less effective synthesis of this last compound from D-glucose is also described. Various physicochemical as well as certain toxicological properties of compound 4 are reported and compared to those established for the now commercially available Cyrene® (2). Such studies reveal that there are significant enough differences in the properties of the sustainably-derived Cyrene® (2) and isomer 4 (iso-Cyrene) to suggest they will exert complementary effects as solvents in a range of settings.